Stent alignment during treatment of a bifurcation

ABSTRACT

A system for treating a bifurcation includes a first radially expandable stent and a second radially expandable stent. The first stent has a side hole and a plurality of lateral elements extending from the side hole. The second stent has a plurality of axial elements extending away from the proximal end of the second stent. The axial elements of the second stent interdigitate with the lateral elements of the first stent when both stents have been expanded.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/313,742 filed Jun. 24, 2014 now U.S. Pat. No. 9,855,158,which is a divisional of U.S. patent application Ser. No. 13/071,183filed Mar. 24, 2011 now U.S. Pat. No. 8,808,347, which is anon-provisional of and claims the benefit of U.S. Provisional PatentApplication No. 61/317,121 filed Mar. 24, 2010; the present applicationis also a continuation-in-part of PCT Application No. PCT/US2009/058505filed Sep. 25, 2009 which is a non-provisional of and claims the benefitof U.S. Provisional Patent Application No. 61/194,346 filed Sep. 25,2008; the entire contents of which are incorporated herein by reference.

The present application is related to U.S. application Ser. No.13/071,149 (Allowed); Ser. No. 13/071,251 (Allowed); Ser. No. 13/071,239(Allowed); Ser. No. 13/071,198 (Allowed); and Ser. No. 13/071,162(Allowed); all of which were filed on Mar. 24, 2011 and are incorporatedherein by reference in their entirety for all purposes. The presentapplication is also related to U.S. Provisional Appln. Nos. 61/317,105;61/317,198; 61/317,114; and 61/317,130; all of which were filed on Mar.24, 2010, and are incorporated herein by reference in their entirety forall purposes.

BACKGROUND OF THE INVENTION

The present invention relates to medical devices, and more particularlyto stenting and treatment of bifurcated vessels. A stent is animplantable scaffold that is typically delivered percutaneously anddeployed in a vein, artery, or other tubular body organ for treating anocclusion, stenosis, aneurysm, collapse, dissection, or weakened,diseased, or abnormally dilated vessel or vessel wall. The stent isradially expanded in situ, thereby expanding and/or supporting thevessel wall or body organ wall. In particular, stents are quite commonlyimplanted in the coronary, cardiac, pulmonary, neurovascular, peripheralvascular, renal, gastrointestinal and reproductive systems, and havebeen successfully implanted in the urinary tract, the bile duct, theesophagus, the tracheo-bronchial tree and the brain, to reinforce thesebody organs.

Stents are often used for improving angioplasty results by preventingelastic recoil and remodeling of the vessel wall and for treatingdissections in blood vessel walls caused by balloon angioplasty ofcoronary arteries, as well as peripheral arteries, by pressing togetherthe intimal flaps in the lumen at the site of the dissection.Conventional stents have been used for treating more complex vascularproblems, such as lesions at or near bifurcation points in the vascularsystem, where a secondary artery branches out of a typically larger,main artery, with limited success rates.

Conventional stent technology is relatively well developed. Conventionalstent designs typically feature a straight tubular, single type cellularstructure, configuration, or pattern that is repetitive throughtranslation along the longitudinal axis. In many stent designs, therepeating structure, configuration, or pattern has strut and connectingballoon catheter portions that can impede blood flow at vesselbifurcations.

Furthermore, the configuration of struts and connecting balloon catheterportions may obstruct the use of post-operative devices to treat adaughter vessel in the region of a vessel bifurcation. For example,deployment of a first stent in the mother lumen may prevent a physicianfrom inserting a daughter stent through the ostium of a daughter vesselof a vessel bifurcation in cases where treatment of the mother vessel issuboptimal because of displaced diseased tissue (for example, due toplaque shifting or “snow plowing”), occlusion, vessel spasm, dissectionwith or without intimal flaps, thrombosis, embolism, and/or othervascular diseases. A regular stent is designed in view of conflictingconsiderations of coverage versus access. For example, to promotecoverage, the cell structure size of the stent may be minimized foroptimally supporting a vessel wall, thereby preventing or reducingtissue prolapse. To promote access, the cell size may be maximized forproviding accessibility of blood flow and of a potentially futureimplanted daughter stent to daughter vessels, thereby preventing “stentjailing,” and minimizing the amount of implanted material. Regular stentdesign has typically compromised one consideration for the other in anattempt to address both. Problems the present inventors observedinvolving daughter jailing, fear of plaque shifting, total occlusion,and difficulty of the procedure are continuing to drive the presentinventors' into the development of novel, delivery systems, which areeasier, safer, and more reliable to use for treating the above-indicatedvariety of vascular disorders. Although conventional stents areroutinely used in clinical procedures, clinical data shows that thesestents are not capable of completely preventing in-stent restenosis(ISR) or restenosis caused by intimal hyperplasia. In-stent restenosisis the reoccurrence of the narrowing or blockage of an artery in thearea covered by the stent following stent implantation. Patients treatedwith coronary stents can suffer from in-stent restenosis.

Additionally, alignment of the side branch stent with the main branchstent can be challenging. If the two stents are not properly aligned,the ends of the stent may overlap with one another resulting in metal ontop of metal, an undesirable situation. Also, if the two stents are notproperly aligned, a gap may exist between the ends of the stent,resulting in an unstented or unscaffolded region in the vessel.Moreover, the unstented region may not receive a drug that is elutedfrom the stent. Thus, the unstented region may be more likely toexperience restenosis. It would therefore be desirable for the sidebranch stent and the main branch stent to accurately align with oneanother upon expansion into the bifurcation.

Many pharmacological attempts have been made to reduce the amount ofrestenosis caused by intimal hyperplasia. Many of these attempts havedealt with the systemic delivery of drugs via oral or intravascularintroduction. However, success with the systemic approach has beenlimited.

Systemic delivery of drugs is inherently limited since it is difficultto achieve constant drug delivery to the afflicted region and sincesystemically administered drugs often cycle through concentration peaksand valleys, resulting in time periods of toxicity and ineffectiveness.Therefore, to be effective, anti-restenosis drugs should be delivered ina localized manner. One approach for localized drug delivery utilizesstents as delivery vehicles. For example, stents seeded with transfectedendothelial cells expressing bacterial betagalactosidase or humantissue-type plasminogen activator were utilized as therapeutic proteindelivery vehicles. See, e.g., Dichek, D. A. et al., “Seeding ofIntravascular Stents With Genetically Engineered Endothelial Cells,”Circulation, 80:1347-1353 (1989). U.S. Pat. No. 5,679,400, InternationalPatent Publication No. WO 91/12779, entitled “Intraluminal Drug ElutingProsthesis,” and International Patent Publication No. WO 90/13332,entitled “Stent With Sustained Drug Delivery” disclose stent devicescapable of delivering antiplatelet agents, anticoagulant agents,antimigratory agents, antimetabolic agents, and other anti-restenosisdrugs. U.S. Pat. Nos. 6,273,913; 6,383,215; 6,258,121; 6,231,600;5,837,008; 5,824,048; 5,679,400; and 5,609,629 teach stents coated withvarious pharmaceutical agents such as Rapamycin, 17-beta-estradiol,Taxol and Dexamethasone. This and all other referenced patents areincorporated herein by reference in their entirety. Furthermore, where adefinition or use of a term in a reference, which is incorporated byreference herein is inconsistent or contrary to the definition of thatterm provided herein, the definition of that term provided hereinapplies and the definition of that term in the reference does not apply.

Therefore, given the challenges of current stent technology, a needexists for improved stent delivery systems and methods, particularly fortreating bifurcated vessels. At least some of these objectives will bemet by the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to methods and delivery systems used todeliver stents in a bifurcated vessel. Embodiments may be configured tostent at least a portion of a mother vessel and a portion of a daughtervessel.

In a first aspect of the present invention, a system for treating abifurcation comprises a first radially expandable stent and a secondradially expandable stent. The first stent comprises a proximal end, adistal end, a sidewall having a side hole therethrough, and a pluralityof lateral elements extending from the side hole. The first radiallyexpandable stent has a collapsed configuration and an expandedconfiguration. In the collapsed configuration the first radiallyexpandable stent is configured for delivery to the bifurcation. In theexpanded configuration the first radially expandable stent supports avessel wall at and/or adjacent the bifurcation. The second stentcomprises a proximal end, a distal end, and a plurality of axialelements extending axially away from the proximal end of the secondstent. The second stent has a collapsed configuration and an expandedconfiguration. In the collapsed configuration, the second radiallyexpandable stent is configured for delivery to the bifurcation. In theexpanded configuration the second radially expandable stent supports avessel wall adjacent the bifurcation. The axial elements of the secondstent interdigitate with the lateral elements of the first stent whenthe first stent and the second stent are in the expanded configuration.

In preferred embodiments, at least one stent has a sidewall with a sidehole or aperture extending therethrough, and a portion of a deliverycatheter may pass through the side hole. However, this is not intendedto be limiting, and in any of the embodiments disclosed herein, one ofskill in the art will appreciate that the stent may have another exitpoint. Thus the delivery catheter may pass through the exit point,whether it is a side hole in a side wall of the stent, or disposed inanother portion of the stent.

The first radially expandable stent or the second radially expandablestent may be balloon expandable. The plurality of axial elements maycomprise a plurality of interconnected struts, or they may comprise astrut that is formed into a series of peaks and valleys. The pluralityof lateral elements may comprise a plurality of interconnected struts,or they may comprise a strut formed into a series of peaks and valleys.The system may further comprise a therapeutic agent that is disposed onthe first or the second radially expandable stents, or on one or both ofthe expandable members. The therapeutic agent may be adapted to beingeluted therefrom, and may comprise an anti-restenosis agent.

The system may further comprise a first delivery catheter and a seconddelivery catheter. The first delivery catheter may comprise a firstelongate shaft with a proximal end and a distal end, and a firstexpandable member adjacent the distal end of the first elongate shaft.The first radially expandable stent may be disposed over the firstexpandable member, and in the collapsed configuration, the first stentmay be coupled with the first expandable member. The second deliverycatheter may comprise a second elongate shaft with a proximal end, adistal end, and a second expandable member adjacent the distal end ofthe second elongate shaft. The second stent may be disposed over thesecond expandable member. In the collapsed configuration, the secondstent may be coupled with the second expandable member. A portion of thesecond delivery catheter may be disposed under a portion of the firstradially expandable stent, and a portion of the second delivery cathetermay pass through the side hole in the first radially expandable stent.The second delivery catheter may be axially slidable relative to thefirst delivery catheter while the first radially expandable stent is inthe collapsed configuration.

The first expandable member and the second expandable member may beindependently expandable of one another. The first expandable member orthe second expandable member may comprise a balloon. One of the firstexpandable member or the second expandable member may comprise a workinglength having a tapered region. The proximal portion of the taperedregion may have a diameter that is larger than a distal portion of thetapered region. Each of the first and second delivery catheters maycomprise a guidewire lumen. Either the first or the second deliverycatheter may comprise a distal guidewire opening in the distal end ofthe respective elongate shaft, and a proximal guidewire opening. Theproximal guidewire opening may be spaced closer to the distal guidewireopening than the proximal end of the respective elongate shaft. Theproximal guidewire opening may be disposed in the proximal end of therespective shaft such that the proximal guidewire opening may be closerto the proximal end of the respective shaft than the distal guidewireopening. The guidewire lumen may be configured to slidably receive aguidewire, and the guidewire lumen may extend from the distal guidewireopening to the proximal guidewire opening.

The second expandable member may be axially spaced apart from the firstexpandable member such that the second expandable member is distal tothe first expandable member. The distal expandable member may have across-sectional profile smaller than a cross-sectional profile of theother expandable member. The first radially expandable stent may benon-uniformly crimped to the first expandable member. The secondradially expandable stent may be uniformly crimped to the secondexpandable member. The second expandable member may have a workinglength, and the length of the second stent may be less than the workinglength. The first elongate shaft may comprise a first radiopaque markerdisposed thereon, and the second elongate shaft may comprise a secondradiopaque marker disposed thereon. When the first marker is alignedwith the second marker a working portion of the first expandable membermay be aligned with a working portion of the second expandable member, aproximal end of the second stent may be aligned with the side hole ofthe first stent, and a proximal portion of the second expandable membermay be disposed under a proximal portion of the first stent. Expansionof the second expandable member may simultaneously expand a portion ofthe first stent and the second stent.

In another aspect of the present invention, a method for treating abifurcated vessel comprises providing a first radially expandable stentand a second radially expandable stent. The first stent comprises aproximal end, a distal end, a sidewall having a side hole therethrough,and a plurality of lateral elements extending from the side hole. Thefirst stent has a collapsed configuration and an expanded configuration.The second stent comprises a proximal end, a distal end, and a pluralityof axial elements extending axially away from the proximal end of thesecond radially expandable stent. The second stent has a collapsedconfiguration and an expanded configuration. The first stent and thesecond stent are both delivered in the collapsed configuration to abifurcation in a vessel. One of the stents is delivered to a side branchof the bifurcation, and the other stent is delivered to a main branch ofthe bifurcation. The first stent is radially expanded from the collapsedconfiguration to the expanded configuration. In the expandedconfiguration the first stent engages and supports a vessel walladjacent the bifurcation. The second stent is radially expanded from thecollapsed configuration to the expanded configuration. In the expandedconfiguration the second stent engages and supports a vessel walladjacent the bifurcation. The axial elements of the second stent areinterdigitated with the lateral elements of the first stent.

The step of delivering the first stent and the second stent may compriseintravascularly advancing a first elongate shaft and a second elongateshaft toward the bifurcation. The first stent may be disposed over thefirst elongate shaft, and the second stent may be disposed over thesecond elongate shaft. The step of delivering the first and the secondstents may comprise slidably advancing a portion of the second elongateshaft under a proximal portion of the first stent, and passing anotherportion of the second elongate shaft through the side hole of the firststent. The side branch may have a diameter that is substantiallyequivalent to the diameter of the main branch. The step of deliveringthe first stent and the second stent may comprise proximally retractingthe proximal end of the second stent toward the side hole of the firststent.

Either the first stent or the second stent may be disposed over anexpandable member, and the step of radially expanding the first stent orthe step of radially expanding the second stent may comprise expandingthe expandable member. The expandable member may comprise a balloon, andthe step of expanding the expandable member may comprise inflating theballoon. The step of radially expanding the first stent may compriseradially expanding a proximal portion of the first stent simultaneouslywith the radial expansion of the second stent. The step of radiallyexpanding the first stent may comprise radially expanding a distalportion of the first stent after the radial expansion of the secondstent.

The plurality of axial elements may comprise one or more struts formedinto a series of peaks and valleys, and the plurality of lateralelements may comprise one or more struts formed into a series of peaksand valleys. The step of interdigitating may comprise positioning a peakon one of the axial elements into a valley on a lateral element, orpositioning a peak on one of the lateral elements into a valley on oneof the axial elements. The interdigitating axial and lateral elementsmay provide uniform or continuous scaffolding around the bifurcation.

The method may further comprise eluting a therapeutic agent from eitherthe first stent, the second stent, or one of the expandable members,into a lesion adjacent the bifurcation. The therapeutic agent maycomprise an anti-restenosis agent. The method may further compriseproximally retracting the second stent toward the side hole in the firststent. The first stent may be disposed over a first elongate shaft, andthe second stent may be disposed over a second elongate shaft. The stepof proximally retracting the second stent may comprise proximallyretracting a portion of the second shaft under a proximal portion of thefirst stent, and passing another portion of the second shaft through theside hole of the first stent. The first elongate shaft may comprise afirst radiopaque marker adjacent the proximal end of the first stent,and the second elongate shaft may comprise a second radiopaque markeradjacent the proximal end of the second stent. The step of proximallyretracting the second stent may comprise aligning the first radiopaquemarker with the second radiopaque marker.

In still another aspect of the present invention, a method for treatinga bifurcated vessel comprises providing a first delivery catheter and asecond delivery catheter. The first delivery catheter comprises a firstelongate shaft, a first expandable member, and a first stent disposedover the first expandable member. The second catheter comprises a secondelongate shaft, a second expandable member, and a second stent disposedover the second expandable member. A portion of the first elongate shaftis disposed under the second stent and the first elongate shaft exits aside hole in the second stent. The first expandable member is distal tothe second expandable member. Both the first delivery catheter and thesecond delivery catheter are advanced through a main branch vesselhaving a lesion to a bifurcation in the main branch. The bifurcationcomprises a side branch vessel having a lesion and extending from themain branch vessel. The first stent is advanced into the side branch,distal to the side branch lesion. A portion of the first expandablemember is proximally refracted under a portion of the second stent. Thefirst expandable member is radially expanded, thereby expanding the sidehole and aligning the side hole with the ostium of the side branch.Expanding the first expandable member also simultaneously expands thefirst stent into engagement with the lesion in the side branch andexpands a proximal portion of the second stent.

The method may further comprise radially expanding the second expandablemember, thereby further expanding the proximal portion of the secondstent and expanding a distal portion of the second stent into engagementwith a wall of the main branch. The method may also comprisesimultaneously expanding the first and the second expandable membersinto engagement with one another thereby ensuring engagement of thefirst stent with the side branch lesion and engagement of the secondstent with the main branch lesion. This also ensures alignment of aproximal end of the first stent with the side hole in the second stent.Alignment may be achieved without distorting the vessel or withoutdistorting the stent struts beyond their intended deformationconfiguration.

In yet another aspect of the present invention, a method for treating abifurcated vessel comprises providing a first delivery catheter and asecond delivery catheter. The first delivery catheter comprises a firstelongate shaft, a first expandable member, and a first stent disposedover the first expandable member. The second delivery catheter comprisesa second elongate shaft, a second expandable member, and a second stentdisposed over the second expandable member. A portion of the firstelongate shaft is disposed under the second stent and the first elongateshaft exits a side hole in the second stent. The first expandable memberis distal to the second expandable member. Both the first deliverycatheter and the second delivery catheter are advanced through a mainbranch vessel having a lesion to a bifurcation in the main branch. Thebifurcation comprises a side branch vessel having a lesion and extendingfrom the main branch vessel. The first stent is advanced into the mainbranch distal to the bifurcation, and the second stent is advanced intothe side branch adjacent the side branch lesion. A portion of the firstexpandable member is proximally retracted under a portion of the secondstent. The first expandable member is radially expanded therebyexpanding the side hole and aligning the side hole with the main branchlumen. Expanding the first expandable member also simultaneously expandsthe first stent into engagement with the lesion in the main branch andexpands a proximal portion of the second stent.

The method may further comprise radially expanding the second expandablemember, thereby further expanding the proximal portion of the secondstent and expanding a distal portion of the second stent into engagementwith a wall of the side branch. The method may also comprisesimultaneously expanding the first and the second expandable membersinto engagement with one another. This ensures engagement of the firststent with the main branch lesion and ensures engagement of the secondstent with the side branch lesion, as well as ensuring alignment of aproximal end of the first stent with the side hole in the second stent.Alignment may be achieved without distorting the vessel or withoutdistorting the stent struts beyond their intended deformationconfiguration.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate an exemplary embodiment of a system having anover-the-wire mother catheter and a rapid exchange daughter catheter.

FIGS. 2A-2B illustrate an exemplary embodiment of a system having anover-the-wire daughter catheter and a rapid exchange mother catheter.

FIGS. 3A-3B illustrate an exemplary embodiment of a system having arapid exchange mother catheter and a rapid exchange daughter catheter.

FIGS. 4A-4B illustrate an exemplary embodiment of a system having anover-the-wire mother catheter and an over-the-wire daughter catheter.

FIGS. 5A-5B illustrate another exemplary embodiment of a system having acapture tube, an over-the-wire mother catheter, and a rapid exchangedaughter catheter.

FIGS. 6A-6B illustrate another exemplary embodiment of a system having acapture tube, an over-the-wire daughter catheter, and a rapid exchangemother catheter.

FIGS. 7A-7B illustrate another exemplary embodiment of a system having acapture tube, a rapid exchange mother catheter, and a rapid exchangedaughter catheter.

FIGS. 8A-8B illustrate another exemplary embodiment of a system having acapture tube, an over-the-wire mother catheter, and an over-the-wiredaughter catheter.

FIGS. 9A-9B illustrate yet another exemplary embodiment of a systemhaving a removable capture tube, an over-the-wire mother catheter and arapid exchange daughter catheter.

FIGS. 10A-10B illustrate yet other exemplary embodiment of a systemhaving a removable capture tube, an over-the-wire daughter catheter anda rapid exchange mother catheter.

FIGS. 11A-11B illustrate yet another exemplary embodiment of a systemhaving a removable capture tube, a rapid exchange mother catheter and arapid exchange daughter catheter.

FIGS. 12A-12B illustrate yet another exemplary embodiment of a systemhaving a removable capture tube, an over-the-wire mother catheter and anover-the-wire daughter catheter.

FIGS. 13A-13C illustrate still another exemplary embodiment of a systemhaving a snap fitting, an over-the-wire mother catheter and a rapidexchange daughter catheter.

FIGS. 14A-14C illustrate still another exemplary embodiment of a systemhaving a snap fitting, an over-the-wire daughter catheter and a rapidexchange mother catheter.

FIGS. 15A-15C illustrate still another exemplary embodiment of a systemhaving a snap fitting, a rapid exchange mother catheter and a rapidexchange daughter catheter.

FIGS. 16A-16C illustrate still another exemplary embodiment of a systemhaving a snap fitting, an over-the-wire mother catheter and anover-the-wire daughter catheter.

FIGS. 17A-17C illustrate another exemplary embodiment of a system havinga snap fitting, an over-the-wire mother catheter and a rapid exchangedaughter catheter.

FIGS. 18A-18C illustrate another exemplary embodiment of a system havinga snap fitting, an over-the-wire daughter catheter and a rapid exchangemother catheter.

FIGS. 19A-19C illustrate another exemplary embodiment of a system havinga snap fitting, a rapid exchange mother catheter and a rapid exchangedaughter catheter.

FIGS. 20A-20C illustrate another exemplary embodiment of a system havinga snap fitting, an over-the-wire mother catheter and an over-the-wiredaughter catheter.

FIGS. 21A-21B illustrate yet another exemplary embodiment of a systemhaving an over-the-wire mother catheter and a rapid exchange daughtercatheter.

FIGS. 22A-22B illustrate yet another exemplary embodiment of a systemhaving an over-the-wire daughter catheter and a rapid exchange mothercatheter.

FIGS. 23A-23B illustrate yet another exemplary embodiment of a systemhaving a rapid exchange mother catheter and a rapid exchange daughtercatheter.

FIGS. 24A-24B illustrate yet another exemplary embodiment of a systemhaving an over-the-wire mother catheter and an over-the-wire daughtercatheter.

FIGS. 25A-25B, 26A-26B, 27A-27B, 28A-28B, 29A-29B, and 30A-30Billustrate an exemplary method of treating a bifurcation.

FIG. 31 illustrates an exemplary embodiment of a stent.

FIG. 32 illustrates an exemplary embodiment of a system having a mothercatheter and a daughter catheter.

FIG. 33 highlights the distal portion of the system illustrated in FIG.32.

FIG. 34 illustrates alignment of the stents in FIGS. 32-33.

FIG. 35 illustrates a cross-section of a stent crimped over a mothercatheter and a daughter catheter.

FIG. 36 illustrates a stent disposed over a mother catheter and adaughter catheter.

FIG. 37 illustrates a stent disposed over a mother catheter and adaughter catheter, and a stent disposed over the daughter catheter.

FIGS. 38A-38M illustrate an exemplary method of treating a bifurcation.

FIGS. 39A-39M illustrate another exemplary method of treating abifurcation.

FIGS. 40A-40H illustrate various stents that may be used with thesystems and methods disclosed herein to treat bifurcations.

FIGS. 41A-41C illustrate the interface between a side branch stent and amain branch stent.

FIGS. 42A-42B illustrate continuous scaffolding in a bifurcation.

FIGS. 43-45 illustrate possible interfaces between a side branch stentand a main branch stent.

FIGS. 46A-46D illustrate exemplary embodiments of a side branch stentinterdigitating with a side hole in main branch stent.

FIGS. 47A-47B illustrate alternative balloon configurations.

FIG. 48 illustrates an exemplary embodiment of a fixed wire catheterhaving a balloon attached to a distal portion of the shaft.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to delivery systems for delivery of stentsto vessel bifurcations having a main branch and a side branch, and isgenerally configured to at least partially cover a portion of a the sidebranch as well as a portion of the main branch. However, this is notintended to be limiting, and one of skill in the art will appreciatethat the devices and methods described herein may be used for treatingother regions of the body.

The scientific community is slowly moving away from a main branch vs.side branch model and nomenclature. It is now well accepted that a“mother” vessel bifurcates into two “daughter vessels,” the two vesselsthat are anatomically after the carina. The vessel that appears to bethe continuation of the mother vessel is usually less angulated, and maybe the larger of the two daughter vessels. The other vessel isfrequently smaller in diameter and may be commonly referred to as theside branch, or a daughter vessel. Therefore, in this specification, theterms “main branch,” “trunk,” or “mother vessel” may be usedinterchangeably. Also in this specification, the terms “side branchvessel” and “daughter vessel” may also be used interchangeably. Theterms “main branch stent,” “trunk stent,” or “mother stent” areinterchangeable, and the term “side branch stent” is alsointerchangeable with the term “daughter stent.” In the case where a mainbranch vessel bifurcates into two equally sized branches, one of thebranches may still be considered to be the main branch or mother vessel,and the other branch may be considered a side branch or daughter vessel.

A variety of catheter designs may be employed to deploy and position themother and daughter stents. Such catheters may be used in connectionwith multiple guidewires that terminate in the mother and daughtervessels. These guidewires may be used to facilitate introduction of thecatheter, any angioplasty balloons, any stents, and/or to properlyorient the stent or balloon within the vessel.

In general, the methods disclosed herein may utilize a catheter systemcomprising a catheter body having a mother vessel guidewire lumen and adaughter vessel balloon that is independently operable and coupled tothe catheter body. The daughter balloon catheter portion has a daughtervessel guidewire lumen. The catheter system further includes a mothercatheter balloon, and a stent is disposed over the balloon. The daughtercatheter portion extends into the proximal opening of the mother stentand exits the mother stent through a side passage of the mother stent.

According to one method, a mother vessel guidewire is inserted into themother vessel until a distal end of the mother vessel guidewire passesbeyond the ostium of the daughter vessel, and a daughter vesselguidewire is inserted into the mother vessel until a distal end of thedaughter vessel guidewire passes into the daughter vessel. To preventthe crossing of guidewires, the two vessels are wired through aguidewire catheter with two lumens to keep the guidewires separate anduntangled.

The guidewire catheter is then removed and a wire separator is placed onthe wires to keep the guidewires unwrapped. The catheter system is thenadvanced over the mother and daughter vessel guidewires, with the motherand daughter vessel catheters passing over the mother vessel guidewireand the daughter vessel guidewire. The catheter system is advanced onboth wires with the daughter vessel balloon catheter portion distal tothe mother balloon catheter portion leading the system. As the cathetersystem advances over the wires, the daughter vessel balloon will enterthe daughter vessel and may be positioned after or simultaneously withplacement of the mother vessel balloon. The mother balloon catheterportion of the catheter system is then advanced distally as far as itcan be advanced where it is stopped by the carina. It can not beadvanced beyond the bifurcation site because the tension of the daughtercatheter on the mother stent will prevent the mother catheter frommoving distally. At this time the distal portion of the mother stent isbeyond the carina in the mother vessel and cannot be advanced anyfurther. This method facilitates advancement of the catheter system tothe bifurcation, which may be necessary for tortuous or calcifiedcoronaries. Once the catheter system is in place the daughter vesselballoon catheter portion is then pulled back relative to the mothercatheter so that the proximal part of the daughter balloon is partiallywithin the mother stent. Alignment can be performed with radiopaquemarkers, in that the proximal markers on the two balloons are next toeach other. The operator can then gently push the catheter system distalto maximize apposition to the carina. The daughter balloon which is nowpartially under the mother stent is then inflated to ensure properalignment of the mother stent. The daughter balloon may also have astent on its distal portion, which would result in the proximal portionof the mother stent and the daughter stent to expand simultaneously. Thedaughter balloon is then deflated.

The mother balloon is then inflated which deploys the mother stent.Kissing, reinflation, of the two balloons is performed if necessary orfor shifting plaque. The catheter system may be removed while the wiresremain in place. In this embodiment, or any of the other embodimentsdisclosed herein, an angioplasty catheter may be used to predilate thevessel and lesion prior to stenting. In some embodiments, primarystenting is employed where the stent is deployed without thepredilation. The two vessels may be angioplastied separately ifpredilatation is indicated on occasion.

In an alternative method, the mother catheter can be mounted on thedaughter vessel guidewire and the daughter catheter can be mounted onthe mother vessel guidewire. In daughter vessels with a high degree ofangularity, for example, when the bifurcation angle is greater thanabout 60-70°, the friction between catheters is lower when the operatorneeds to draw the daughter stent proximally along the main branch andinto the mother stent, as opposed to the prior configuration where thedaughter stent is drawn along the side branch into the mother stent. Thecatheter system is advanced so the daughter balloon catheter leads thesystem and passes the ostium of the daughter vessel, while remaining inthe mother vessel. As the catheter system is advanced further, themother balloon catheter will enter the daughter vessel. The cathetersystem can only be advanced a certain distance toward the bifurcation,until it is stopped by the carina. It cannot be advanced beyond thebifurcation site because the tension of the daughter catheter on themother stent will prevent the mother catheter from moving distally. Atthis time the distal portion of the mother stent is beyond the ostium ofthe daughter vessel and cannot be advanced any further. While the mothercatheter is held in place, the daughter catheter is drawn back such thatthe proximal portion of the daughter balloon is partially in the motherstent. Alignment can be performed with radiopaque markers, in that theproximal markers on the two balloons are next to each other. Theoperator can then gently push the catheter system distally to maximizeapposition to the carina. A stent on the daughter balloon (which is nowpartially under the mother stent) is aligned so that when the daughterballoon is inflated the daughter stent and the proximal portion of themother stent expand simultaneously and give complete coverage of themother vessel. The daughter vessel balloon is then deflated. The mothervessel balloon is then inflated and the distal portion of the motherstent is expanded. A kissing procedure can also be performed ifrequired.

The mother vessel can be stented if necessary with any commerciallyavailable stent. A balloon on a wire could be used as an alternative tothe daughter catheter. In an alternative embodiment, the catheter systemcan be arranged with the daughter balloon portion proximal to the motherballoon portion and advanced over the guidewires to the bifurcation. Inthe case of the mother catheter on the mother guidewire, the alignmentof the mother stent with the ostium of the daughter vessel occursbecause tension between the daughter guidewire and mother stent on themother catheter prevents further advancement of the mother catheter. Inthe alternative case of the mother catheter on the daughter guidewire,the alignment of the mother stent with the ostium of the mother vesseloccurs because tension between the mother guidewire and mother stent onthe mother catheter (on the daughter guidewire) prevents furtheradvancement of the mother catheter. In both cases the daughter stent isadvanced into alignment with the mother stent and expanded. In preferredembodiments, the mother catheter is an over-the-wire (OTW) design andthe daughter catheter is a rapid-exchange (RX) design with daughtercatheter portion preferably distal thereto. The daughter balloon isplaced just distal to the tip of the mother catheter, this arrangementminimizes the overall profile of the catheter system and allows maximaltracking of the arteries. The system may additionally have stentscrimped over the balloons. The daughter stent may be any length, but inpreferred embodiments is approximately half the length of the daughterballoon or mother stent. The proximal end of the mother stent may becrimped only slightly to allow the daughter catheter balloon portion tooperate independently so that it may be pushed or pulled withoutdislodging the mother stent.

An exemplary method comprises the following steps:

1. Advance the catheter system to bifurcation, daughter balloon catheterportion and mother balloon catheter portion in their respective vessels.

2. The mother catheter is no longer able to advance because of thetension between the mother stent and daughter catheter.

3. The daughter balloon proximal portion is drawn back into the motherstent and aligned with radiopaque markers.

4. While holding both the mother and daughter catheters tightly, theoperator pushes forward lightly.

5. Inflate the daughter balloon and expand the daughter stent,approximately half of the daughter balloon distal portion will expandthe “half-stent,” and half of the daughter balloon proximal portion willexpand inside the mother vessel and partially expand the proximalportion of the mother stent. Expansion of the proximal portion of themother stent and the daughter stent preferably occur simultaneously.

6. Once the daughter stent is fully deployed, then the mother ballooncan be fully expanded to deploy the distal portion of the mother stent.

7. A conventional kissing procedure may be utilized to ensure fullapposition. In one particular aspect, the daughter balloon catheterportion may be used without a stent. This allows perfect alignment ofthe mother stent around the ostium of the daughter vessel. The daughterballoon would be used for the alignment as outlined in step three above,and expands the proximal portion of the mother stent.

In an alternative embodiment, the mother catheter is an over-the-wire(OTW) design and the daughter catheter is a rapid-exchange (RX) designwith daughter catheter portion distal thereto. The system mayadditionally have stents crimped over the balloons. The daughter stentis preferably less than the length of the mother balloon or stent,although this is not intended to be limiting, and the daughter stent maybe any length. The proximal end of the mother stent may be partiallycrimped to allow the daughter catheter balloon portion to operateindependently, so that it may be pushed or pulled without restrictionand minimum friction, and without dislodging or affecting the motherstent. An exemplary method comprises the following steps:

1. Looping the OTW so that one operator can hold both guide wires withone hand and then push both catheters with the other.

2. Advance the catheter system to bifurcation, daughter balloon catheterportion and mother balloon catheter portion aligned in their respectivevessels, as disclosed in steps two through three in the aboveembodiment.

3. While holding both the mother and daughter catheters tightly, pushthe catheter system forward until the mother balloon catheter portion isstopped at the carina.

4. Inflate the daughter balloon and expand the daughter stent,approximately half of the daughter balloon distal portion will expandthe “half-stent,” and half of the daughter balloon proximal portion willexpand inside the mother vessel and partially expand the proximalportion of the mother stent.

5. Once the daughter stent is fully deployed, then the mother ballooncan be fully expanded to deploy the distal portion of the mother stent.

6. A conventional kissing procedure may be utilized to ensure fullapposition.

In one particular aspect, the daughter balloon catheter portion may beused without a stent. This would allow perfect alignment of the motherstent around the ostium of the daughter vessel. The daughter balloonwould be used for the alignment as outlined in step three above, andexpand the proximal portion of the mother stent.

In an alternative embodiment, the mother catheter is an over-the-wiredesign and the daughter catheter is a rapid-exchange design withdaughter catheter portion distal thereto. The system may additionallyhave stents crimped over the balloons. The daughter stent may beapproximately half the length of the mother balloon or stent, but thisis not intended to be limiting, and the daughter stent may be anylength. The proximal end of the mother stent may be partially crimped toallow the daughter catheter balloon portion to operate independently, sothat it may be pushed or pulled without dislodging the mother stent. Anexemplary method comprises the following steps:

1. Place the daughter catheter over the guidewire in the daughter vesseland slide the system into the guide catheter without placing the motherballoon over a guidewire at this time. After the leading daughtercatheter enters the coronary artery and just before the mother catheterexits the guide catheter, insert the mother guidewire through the mothercatheter and into the mother vessel, then push the system out of theguide catheter over the two guidewires. This method mitigates wire wrap.

2. Advance the catheter system to the bifurcation, daughter ballooncatheter portion and mother balloon catheter portion aligned in theirrespective vessels.

3. Advance the catheter system to bifurcation, daughter balloon catheterportion and mother balloon catheter portion aligned in their respectivevessels, as disclosed in step two in the above embodiment. Pull thedaughter catheter back until the proximal markers on both balloons arealigned.

4. Inflate the daughter balloon and expand the daughter stent,approximately half of the daughter balloon distal portion will expandthe “half-stent,” and half of the daughter balloon proximal portion willexpand inside the mother vessel and partially expand the proximalportion of the mother stent.

5. Once the daughter stent is fully deployed, then the mother ballooncan be fully expanded to deploy the distal portion of the mother stent.

6. A conventional kissing procedure may be utilized to ensure fullapposition. In one particular aspect, the daughter balloon catheterportion may be used without a stent. This would allow perfect alignmentof mother stent around the ostium of the daughter vessel. The daughterballoon would be used for the alignment as outlined in step three above,and expand the proximal portion of the mother stent.

In an alternative embodiment the mother and daughter systems balloonsare aligned. This embodiment could include the mother stent and daughterstent or either stent. When there is both a mother stent and a daughterstent, the daughter stent is preferably shorter than the mother stent,although it may be any length, and in preferred embodiments isapproximately half the length of the mother stent so that the daughterstent could be mounted on the distal half of the daughter balloon.Furthermore, the proximal portion of the daughter catheter shaft ispositioned under the non-uniformly crimped mother stent. The dual stentarrangement reduces the profile compared to a full length stent thatcovers the entire length of the daughter balloon.

The methods described herein could alternatively include the step offlushing the catheters and the guidewire port to assist withmaneuverability. The methods described herein could alternativelyinclude the step of a couple of snap-on couplers that lock the twocatheters together. In another particular aspect, each balloon catheterportion may include at least one radiopaque marker. With such aconfiguration, separation of the markers may be conveniently observedusing fluoroscopy to indicate that the balloon catheter portions havepassed beyond the ostium and the daughter balloon catheter portion haspassed into the daughter vessel, thus aligning the passage of the stentwith the ostium of the daughter vessel. In another particular aspect,the catheter systems design is contemplated to cover combinations ofrapid exchange and over the wire; for visualization purposes the hybridversions are preferred because they are easier to distinguish whileusing fluoroscopy.

In another particular aspect, the proximal balloon may be differentiallyexpandable, such that one end of the balloon may expand prior to theother end. In another particular aspect, the proximal balloon catheterportion may receive a stent that can be crimped under variable pressureto allow the distal balloon catheter portion freedom of movement.

In another particular aspect, a stent may be crimped over the proximalballoon catheter portion and the stent may be designed to deploy withvariable profile to better oppose the patient anatomy.

In another particular aspect, the distal balloon catheter portion may bedelivered via a pull away or peel away capture tube. All of the aboveembodiments may utilize mother vessel stents having any diameter, withdiameter preferably ranging from about 2.5 to about 5 millimeters, anddaughter vessel stent having any diameter, preferably ranging from about2 to about 5 millimeters. The length of the stents may be any length,preferably in the range of about 4 to about 40 millimeters. The positionof a stent on a catheter need not be fixed and may be positioned oneither or both catheters.

Catheter Configurations:

FIG. 1A illustrates an exemplary embodiment of the catheter system 100with a distal daughter balloon catheter portion comprising a balloonwith a daughter stent crimped thereon. The daughter stent may be shorterthan the mother stent, and it may not be centered on its correspondingballoon in this as well as any other embodiments disclosed herein. Thus,in preferred embodiments, a proximal portion of the daughter balloonremains uncovered by a stent, as will be discussed in greater detailbelow. In a particular embodiment the daughter stent is preferably abouthalf the length of the mother stent. The distal daughter stent iscrimped under standard conditions known in the art. The proximal motherballoon catheter portion comprises a mother balloon and a mother stent.The mother stent is crimped differentially along the longitudinaldirection and circumferentially. In this exemplary embodiment, thedistal half of the mother stent is crimped under typical conditions toensure that the mother stent is not dislodged during the alignment withthe distal daughter balloon. Further, the proximal portion of the motherstent is crimped under non-standard, relatively loose, conditions toallow the distal daughter balloon catheter portion freedom of movementeven though a portion of the daughter balloon catheter portion iscircumferentially enclosed. The mother and daughter catheters areslidably attached to each other via a hollow exchange port. The exchangeport is embedded in the side of the mother over the wire catheter andhas an inner diameter just large enough to allow the insertion of therapid exchange daughter catheter and balloon. The exchange port may beany length that extends between a proximal portion of the balloons and adistal portion of the catheter connectors, and in this embodiment isabout 10 centimeters long, but in preferred embodiments varies fromabout 1 centimeter to about 30 centimeters, and in more preferredembodiments is about 5 cm to about 10 cm long. The entry for thedaughter catheter on the exchange port is proximal and the exit for thedaughter catheter is on the distal end of the exchange port. Thedaughter catheter is loaded through the exchange port and the daughterballoon extends distally from the exit of the exchange port, preferablyabout 5 centimeters. However, it is possible to have the exchange portany distance from the mother balloon, but preferably about 1 to about 30centimeters proximal to the mother balloon. The daughter stent can becrimped on to the balloon after it has been loaded through the exchangeport. The exchange port preferably has a tight fit to reduce catheterprofile and preferably has low friction to allow the operator to easilyslide the catheters relative to each other.

FIG. 1B more clearly illustrates the features of the catheter system 100in FIG. 1A. The stent delivery system 100 includes a first catheter 102,and a second catheter 130. The first catheter 102 includes an elongateshaft 104 with a radially expandable balloon 106 disposed near a distalend of the elongate shaft 104. A stent 108 having a proximal portion122, a distal portion 114 and a side hole 120 is disposed over theballoon 106. The distal portion 114 is crimped to the balloon 106 toprevent ejection during delivery, while the proximal portion 122 ispartially crimped to the balloon 106 so the second catheter 130 may beslidably advanced or retracted under the proximal portion 122 of stent108. The first catheter is an over-the-wire (OTW) catheter having aguidewire lumen 112 extending from the distal guidewire port 110 at thedistal end of the elongate shaft 104 to the proximal end of the elongateshaft 104 into Y-adapter 114 having a connector 116. The connector 116is preferably a Luer connector and this allows easy coupling with asyringe or other device for lumen flushing or injecting contrast media.When unconnected, the guidewire lumen 112 exits via connector 116. Asecond connector 118, also preferably a Luer connector allows attachmentof an Indeflator or other device to the catheter for inflation of theballoon 106 via an inflation lumen (not shown) in the elongate shaft104. The first catheter 102 also includes a hollow exchange port tube124 coupled to the elongate shaft 104. The hollow exchange port tube 124may be coextruded with the first shaft 104, or it may be bonded orotherwise attached thereto using techniques known to those skilled inthe art. The hollow exchange port may alternatively be coupled with theother shaft 132. The hollow exchange port tube 124 includes a centralchannel 126 extending therethrough and is sized to slidably receive aportion of the second catheter 130. Radiopaque markers may be placed atdifferent locations along the shaft 104, often near the balloon 106and/or stent 108, to help mark the proximal and distal ends of the stentor balloon, as well to facilitate alignment of the two catheters duringstent deployment, as discussed elsewhere in this specification.

The second catheter 130 includes an elongate shaft 132 with a radiallyexpandable balloon 140 disposed near a distal end of the elongate shaft132. A stent 142 is disposed over balloon 140. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 142 is shorter than the working length of theballoon 140 so that a proximal portion of the balloon 140 isunconstrained by the stent 142 and this unconstrained portion of theballoon 140 may be slidably advanced or refracted through side hole 120and under proximal portion 122 of stent 108 as will be discussed below.Stent 142 is crimped to balloon 140 to prevent ejection during delivery.At least a portion of balloon 140, and stent 142 are distally offsetrelative to balloon 106 and stent 108 so as to minimize profile of thedevice. In this embodiment the distal stent 142 may be deployed in amain branch of the vessel and the other stent 108 may be deployed in aside branch of the vessel. Alternatively, the distal stent 142 may bedeployed in a side branch of a vessel and the other stent 108 may bedeployed in the main branch of a vessel. The second catheter 130 is arapid exchange catheter (RX) having a guidewire lumen 134 extending fromthe distal guidewire port 138 at the distal end of the elongate shaft132 to a proximal guidewire port 136 which is closer to the distal port138 than the proximal end of the catheter shaft 132. The proximalguidewire port 136 is also unobstructed by the hollow exchange tube 124and preferably proximal thereto. A connector 144, preferably a Luerconnector is connected to the proximal end of the elongate shaft 132 andallows an Indeflator or other device to be coupled with an inflationlumen (not shown) in elongate shaft 132 for inflation of balloon 140. Aportion of shaft 132 is disposed in the central channel 126 of thehollow exchange tube 124 and this helps keep the two catheter shafts104, 132 parallel and prevents tangling during delivery and as shaft 132is slidably advanced or retracted relative to shaft 104. Also, anotherportion of shaft 132 is disposed under proximal portion 122 of stent108. The second catheter 130 may also be slidably advanced or retractedunder the proximal portion 122 of stent 108 so that the shaft 132 passesthrough the side hole 120 in stent 108. Radiopaque markers may be placedat different locations on the shaft 132, often near the balloon 140 orstent 142, to help mark the proximal and distal ends of the stent orballoon, as well to facilitate alignment of the two catheters duringstent deployment, as discussed elsewhere in this specification.

FIG. 2A illustrates a cross sectional view of one embodiment of acatheter system 200 with the daughter catheter balloon portion distal tothe mother balloon portion utilizing the same exchange port as describedin FIG. 1A. The mother balloon is preferably at least about 5centimeters distal from the exit of the exchange port. As disclosedabove the mother balloon could be distal from the exchange port fromabout 1 cm to about 30 centimeters.

FIG. 2B more clearly illustrates the features of the catheter system 200in FIG. 2A. The stent delivery system 200 includes a first catheter 202,and a second catheter 230. The first catheter 202 includes an elongateshaft 204 with a radially expandable balloon 206 disposed near a distalend of the elongate shaft 204, and a stent 208 disposed over the balloon206. The stent 208 may be the same length as the working length of theballoon 208, or it may be shorter. In preferred embodiments, the stent208 is shorter than the working length of balloon 206 such that aproximal portion of balloon 206 remains unconstrained by stent 208. Theproximal portion of balloon 206 may be slidably advanced and retractedunder stent 242 via side hole 220. Stent 208 is crimped to the balloon206 to prevent ejection during delivery. The first catheter is anover-the-wire (OTW) catheter having a guidewire lumen 212 extending fromthe distal guidewire port 210 at the distal end of the elongate shaft204 to the proximal end of the elongate shaft 204 into Y-adapter 214having a connector 216. The connector 216 is preferably a Luer connectorand this allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 212 exits via connector 216. A second connector 218, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 206 via an inflationlumen (not shown) in the elongate shaft 204. The first catheter 202 alsoincludes a hollow exchange port tube 224 coupled to the elongate shaft204. The hollow exchange port tube 224 may be coextruded with the firstshaft 204, or it may be bonded or otherwise attached thereto usingtechniques known to those skilled in the art. The hollow exchange portmay alternatively be coupled with the other shaft 232. The hollowexchange port tube 224 includes a central channel 226 extendingtherethrough and is sized to slidably receive a portion of the secondcatheter 230. Radiopaque markers may be placed at different locationsalong the shaft 204, often near the balloon 206 and/or stent 208, tohelp mark the proximal and distal ends of the stent or balloon, as wellto facilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

The second catheter 230 includes an elongate shaft 232 with a radiallyexpandable balloon 240 disposed near a distal end of the elongate shaft232. A stent 242 having a proximal portion 222, a distal portion 214,and a side hole 220 is disposed over balloon 240. The distal portion 214is crimped to balloon 240 to prevent ejection during delivery, while theproximal portion 222 is partially crimped to balloon 240 so elongateshaft 204 may be slidably advanced or retracted under the proximalportion 222 of stent 242. The stent may preferably have a length thatmatches the working length of the balloon, or the stent length may beshorter than the balloon working length. At least a portion of balloon206, and stent 208 are distally offset relative to balloon 240 and stent242 so as to minimize profile of the device. In this embodiment thedistal stent 208 may be deployed in a main branch of the vessel and theother stent 242 may be deployed in a side branch of the vessel.Alternatively, the distal stent 208 may be deployed in a side branch ofa vessel and the other stent 242 may be deployed in the main branch of avessel. The second catheter 230 is a rapid exchange catheter (RX) havinga guidewire lumen 234 extending from the distal guidewire port 238 atthe distal end of the elongate shaft 232 to a proximal guidewire port236 which is closer to the distal port 238 than the proximal end of thecatheter shaft 232. The proximal guidewire port 236 is also unobstructedby the hollow exchange tube 224 and preferably proximal thereto. Aconnector 244, preferably a Luer connector is connected to the proximalend of the elongate shaft 232 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 232for inflation of balloon 240. A portion of shaft 232 is disposed in thecentral channel 226 of the hollow exchange tube 224 and this helps keepthe two catheter shafts 204, 232 parallel and prevents tangling duringdelivery and as shaft 232 is slidably advanced or retracted relative toshaft 204. Also, a portion of shaft 204 is disposed under proximalportion 222 of stent 242. The first catheter 202 may be slidablyadvanced or retracted under the proximal portion 222 of stent 242 sothat the shaft 204 passes through the side hole 220 in stent 242.Radiopaque markers may be placed at different locations on the shaft232, often near the balloon 240 or stent 242, to help mark the proximaland distal ends of the stent or balloon, as well to facilitate alignmentof the two catheters during stent deployment, as discussed elsewhere inthis specification.

FIG. 3A illustrates a cross sectional view of one embodiment of acatheter system 300 with the mother and daughter catheters both having arapid exchange design. In this particular embodiment one of thecatheters has a hollow exchange port embedded in its side and the othercatheter is loaded through the exchange port. Typically, the catheter isloaded prior to having a stent crimped over the balloon portion.

FIG. 3B more clearly illustrates the features of the catheter system 300in FIG. 3A. The stent delivery system 300 includes a first catheter 302,and a second catheter 330. The first catheter 302 includes an elongateshaft 304 with a radially expandable balloon 306 disposed near a distalend of the elongate shaft 304. A stent 308 having a proximal portion322, a distal portion 314 and a side hole 320 is disposed over theballoon 306. The distal portion 314 is crimped to the balloon 306 toprevent ejection during delivery, while the proximal portion 322 ispartially crimped to the balloon 306 so the second catheter 330 may beslidably advanced under the proximal portion 322 of stent 308. The firstcatheter is a rapid exchange catheter (RX) having a guidewire lumen 312extending from the distal guidewire port 310 at the distal end of theelongate shaft 304 to a proximal guidewire port 311 which is closer tothe distal port 310 than the proximal end of the catheter shaft 304. Aconnector 316 is coupled with the proximal end of the elongate shaft304. The connector 316 is preferably a Luer connector and this allowseasy coupling with an Indeflator or other device for inflation of theballoon 306. The first catheter 302 also includes a hollow exchange porttube 324 coupled to the elongate shaft 304. The hollow exchange porttube 324 may be coextruded with the first shaft 304, or it may be bondedor otherwise attached thereto using techniques known to those skilled inthe art. The hollow exchange port may alternatively be coupled with theother shaft 332. The hollow exchange port tube 324 includes a centralchannel 326 extending therethrough and is sized to slidably receive aportion of the second catheter 330. Radiopaque markers may be placed atdifferent locations along the shaft 304, often near the balloon 306and/or stent 308, to help mark the proximal and distal ends of the stentor balloon, as well to facilitate alignment of the two catheters duringstent deployment, as discussed elsewhere in this specification.

The second catheter 330 includes an elongate shaft 332 with a radiallyexpandable balloon 340 disposed near a distal end of the elongate shaft332. A stent 342 is disposed over balloon 340. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 342 is shorter than the working length of theballoon 340 so that a proximal portion of the balloon 340 isunconstrained by the stent 342 and this unconstrained portion of theballoon 340 may be slidably advanced or refracted through side hole 320and under proximal portion 322 of stent 308 as will be discussed below.Stent 342 is crimped to balloon 340 to prevent ejection during delivery.At least a portion of balloon 340, and stent 342 are distally offsetrelative to balloon 306 and stent 308 so as to minimize profile of thedevice. In this embodiment the distal stent 342 may be deployed in amain branch of the vessel and the other stent 308 may be deployed in aside branch of the vessel. Alternatively, the distal stent 342 may bedeployed in a side branch of a vessel and the other stent 308 may bedeployed in the main branch of a vessel. The second catheter 330 is arapid exchange catheter (RX) having a guidewire lumen 334 extending fromthe distal guidewire port 338 at the distal end of the elongate shaft332 to a proximal guidewire port 336 which is closer to the distal port338 than the proximal end of the catheter shaft 332. The proximalguidewire port 336 is also unobstructed by the hollow exchange tube 324and may be distal thereto. A connector 344, preferably a Luer connectoris connected to the proximal end of the elongate shaft 332 and allows anIndeflator or other device to be coupled with an inflation lumen (notshown) in elongate shaft 332 for inflation of balloon 340. A portion ofshaft 332 is disposed in the central channel 326 of the hollow exchangetube 324 and this helps keep the two catheter shafts 304, 332 paralleland prevents tangling during delivery and as shaft 332 is slidablyadvanced or retracted relative to shaft 304. Also, another portion ofshaft 332 is disposed under proximal portion 322 of stent 308. Thesecond catheter 330 may also be slidably advanced or retracted under theproximal portion 322 of stent 308 so that the shaft 332 passes throughthe side hole 320 in stent 308. Radiopaque markers may be placed atdifferent locations on the shaft 332, often near the balloon 340 orstent 342, to help mark the proximal and distal ends of the stent orballoon, as well to facilitate alignment of the two catheters duringstent deployment, as discussed elsewhere in this specification.

FIG. 4A illustrates a cross sectional view of one embodiment of acatheter system 400 with the mother and daughter catheters both havingan over the wire design. In this particular embodiment one of thecatheters has a hollow exchange port embedded in its side and the othercatheter does not have a hollow exchange port. The catheter without theexchange port is loaded onto the catheter with an exchange port.Typically, the catheter would have to be loaded prior to having a stentcrimped over the balloon portion.

FIG. 4B more clearly illustrates the features of the catheter system 400in FIG. 4A. The stent delivery system 400 includes a first catheter 402,and a second catheter 430. The first catheter 402 includes an elongateshaft 404 with a radially expandable balloon 406 disposed near a distalend of the elongate shaft 404. A stent 408 having a proximal portion422, a distal portion 414 and a side hole 420 is disposed over theballoon 406. The distal portion 414 is crimped to the balloon 406 toprevent ejection during delivery, while the proximal portion 422 ispartially crimped to the balloon 406 so the second catheter 430 may beslidably advanced under the proximal portion 422 of stent 408. The firstcatheter is an over-the-wire (OTW) catheter having a guidewire lumen 412extending from the distal guidewire port 410 at the distal end of theelongate shaft 404 to the proximal end of the elongate shaft 404 intoY-adapter 414 having a connector 416. The connector 416 is preferably aLuer connector and this allows easy coupling with a syringe or otherdevice for lumen flushing or injecting contrast media. When unconnected,the guidewire lumen 412 exits via connector 416. A second connector 418,also preferably a Luer connector allows attachment of an Indeflator orother device to the catheter for inflation of the balloon 406 via aninflation lumen (not shown) in the elongate shaft 404. The firstcatheter 402 also includes a hollow exchange port tube 424 coupled tothe elongate shaft 404. The hollow exchange port tube 424 may becoextruded with the first shaft 404, or it may be bonded or otherwiseattached thereto using techniques known to those skilled in the art. Thehollow exchange port may alternatively be coupled with the other shaft432. The hollow exchange port tube 424 includes a central channel 426extending therethrough and is sized to slidably receive a portion of thesecond catheter 430. Radiopaque markers may be placed at differentlocations along the shaft 404, often near the balloon 406 and/or stent408, to help mark the proximal and distal ends of the stent or balloon,as well to facilitate alignment of the two catheters during stentdeployment, as discussed elsewhere in this specification.

The second catheter 430 includes an elongate shaft 432 with a radiallyexpandable balloon 440 disposed near a distal end of the elongate shaft432. A stent 442 is disposed over balloon 440. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 442 is shorter than the working length of theballoon 440 so that a proximal portion of the balloon 440 isunconstrained by the stent 442 and this unconstrained portion of theballoon 440 may be slidably advanced or refracted through side hole 420and under proximal portion 422 of stent 408 as will be discussed below.Stent 442 is crimped to balloon 440 to prevent ejection during delivery.At least a portion of balloon 440, and stent 442 are distally offsetrelative to balloon 406 and stent 408 so as to minimize profile of thedevice. In this embodiment the distal stent 442 may be deployed in amain branch of the vessel and the other stent 408 may be deployed in aside branch of the vessel. Alternatively, the distal stent 442 may bedeployed in a side branch of a vessel and the other stent 408 may bedeployed in the main branch of a vessel. The second catheter 430 is anover-the-wire (OTW) catheter having a guidewire lumen 434 extending fromthe distal guidewire port 438 at the distal end of the elongate shaft432 to the proximal end of the elongate shaft 432 into Y-adapter 446having a connector 448. The connector 448 is preferably a Luer connectorand this allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 434 exits via connector 448. A second connector 444, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 440 via an inflationlumen (not shown) in the elongate shaft 432. A portion of shaft 432 isdisposed in the central channel 426 of the hollow exchange tube 424 andthis helps keep the two catheter shafts 404, 432 parallel and preventstangling during delivery and as shaft 432 is slidably advanced orretracted relative to shaft 404. Also, another portion of shaft 432 isdisposed under proximal portion 422 of stent 408. The second catheter430 may also be slidably advanced or retracted under the proximalportion 422 of stent 408 so that the shaft 432 passes through the sidehole 420 in stent 408. Radiopaque markers may be placed at differentlocations on the shaft 432, often near the balloon 440 or stent 442, tohelp mark the proximal and distal ends of the stent or balloon, as wellto facilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIGS. 5A, 6A, 7A, and 8A illustrate an end to end capture tube thatconnects the catheters together. The capture tube keeps the cathetersfrom tangling. The capture tube preferably remains in place during theentire clinical procedure. In these exemplary embodiments, the capturetube is a thin polymer hollow straw that covers the mother and daughtercatheters from a point about 10 centimeters distal to the Indeflatorattachment to a distal point that is about 10 centimeters proximal fromthe rapid exchange catheter's proximal rapid exchange port.

FIG. 5A illustrates a catheter system 500 having a distal daughtercatheter with a rapid exchange configuration and a proximal mothercatheter with an over-the-wire configuration. FIG. 5B more clearlyillustrates the features of the catheter system 500 seen in FIG. 5A. Thestent delivery system 500 includes a first catheter 502, and a secondcatheter 530. The first catheter 502 includes an elongate shaft 504 witha radially expandable balloon 506 disposed near a distal end of theelongate shaft 504. A stent 508 having a proximal portion 522, a distalportion 514 and a side hole 520 is disposed over the balloon 506. Thedistal portion 514 is crimped to the balloon 506 to prevent ejectionduring delivery, while the proximal portion 522 is partially crimped tothe balloon 506 so the second catheter 530 may be slidably advancedunder the proximal portion 522 of stent 508. The first catheter is anover-the-wire (OTW) catheter having a guidewire lumen 512 extending fromthe distal guidewire port 510 at the distal end of the elongate shaft504 to the proximal end of the elongate shaft 504 into Y-adapter 514having a connector 516. The connector 516 is preferably a Luer connectorand this allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 512 exits via connector 516. A second connector 518, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 506 via an inflationlumen (not shown) in the elongate shaft 504. The first catheter 502 isdisposed in the central channel 526 of a capture tube 524. Centralchannel 526 is sized to fit both shafts 504, 532 and allow slidablemovement thereof. Shaft 504 is slidable in the central channel 526, orit may be locked with a locking collar 525 such as a Tuohy-Borstcompression fitting. Radiopaque markers may be placed at differentlocations along the shaft 504, often near the balloon 506 and/or stent508, to help mark the proximal and distal ends of the stent or balloon,as well to facilitate alignment of the two catheters during stentdeployment, as discussed elsewhere in this specification.

The second catheter 530 includes an elongate shaft 532 with a radiallyexpandable balloon 540 disposed near a distal end of the elongate shaft532. A stent 542 is disposed over balloon 540. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 542 is shorter than the working length of theballoon 540 so that a proximal portion of the balloon 540 isunconstrained by the stent 542 and this unconstrained portion of theballoon 540 may be slidably advanced or refracted through side hole 520and under proximal portion 522 of stent 508 as will be discussed below.Stent 542 is crimped to balloon 540 to prevent ejection during delivery.At least a portion of balloon 540, and stent 542 are distally offsetrelative to balloon 506 and stent 508 so as to minimize profile of thedevice. In this embodiment the distal stent 542 may be deployed in amain branch of the vessel and the other stent 508 may be deployed in aside branch of the vessel. Alternatively, the distal stent 542 may bedeployed in a side branch of a vessel and the other stent 508 may bedeployed in the main branch of a vessel. The second catheter 530 is arapid exchange catheter (RX) having a guidewire lumen 534 extending fromthe distal guidewire port 538 at the distal end of the elongate shaft532 to a proximal guidewire port 536 which is closer to the distal port538 than the proximal end of the catheter shaft 532. The proximalguidewire port 536 is also unobstructed by the capture tube 524 and maybe distal thereto. A connector 544, preferably a Luer connector isconnected to the proximal end of the elongate shaft 532 and allows anIndeflator or other device to be coupled with an inflation lumen (notshown) in elongate shaft 532 for inflation of balloon 540. A portion ofshaft 532 is disposed in the central channel 526 of the capture tube 524and this helps keep the two catheter shafts 504, 532 parallel andprevents tangling during delivery and as shaft 532 is slidably advancedin the central channel 526. Compression fitting 525 may be used to lockelongate shafts 504, 532 in the capture tube 524 to prevent axialmovement. The compression fitting may be a Tuohy-Borst fitting. Also,another portion of shaft 532 is disposed under proximal portion 522 ofstent 508. The second catheter 530 may also be slidably advanced orretracted under the proximal portion 522 of stent 508 so that the shaft532 passes through the side hole 520 in stent 508. Radiopaque markersmay be placed at different locations on the shaft 532, often near theballoon 540 or stent 542, to help mark the proximal and distal ends ofthe stent or balloon, as well to facilitate alignment of the twocatheters during stent deployment, as discussed elsewhere in thisspecification.

FIG. 6A illustrates a catheter system 600 having a distal daughtercatheter with an over the wire design and a proximal mother catheterwith a rapid exchange design. FIG. 6B more clearly illustrates thefeatures of the catheter system 600 in FIG. 6A. The stent deliverysystem 600 includes a first catheter 602, and a second catheter 630. Thefirst catheter 602 includes an elongate shaft 604 with a radiallyexpandable balloon 606 disposed near a distal end of the elongate shaft604, and a stent 608 disposed over the balloon 606. The stent 608 may bethe same length as the working length of the balloon 608, or it may beshorter. In preferred embodiments, the stent 608 is shorter than theworking length of balloon 606 such that a proximal portion of balloon606 remains unconstrained by stent 608. The proximal portion of balloon606 may be slidably advanced and retracted under stent 642 via side hole620. Stent 608 is crimped to the balloon 606 to prevent ejection duringdelivery. The first catheter is an over-the-wire (OTW) catheter having aguidewire lumen 612 extending from the distal guidewire port 610 at thedistal end of the elongate shaft 604 to the proximal end of the elongateshaft 604 into Y-adapter 614 having a connector 616. The connector 616is preferably a Luer connector and this allows easy coupling with asyringe or other device for lumen flushing or injecting contrast media.When unconnected, the guidewire lumen 612 exits via connector 616. Asecond connector 618, also preferably a Luer connector allows attachmentof an Indeflator or other device to the catheter for inflation of theballoon 606 via an inflation lumen (not shown) in the elongate shaft604. The first catheter 602 is disposed in the central channel 626 of acapture tube 624. Central channel 626 is sized to fit both shafts 604,632 and allow slidable movement thereof. Shaft 604 is slidable in thecentral channel 626, or it may be locked with a locking collar 625 suchas a Tuohy-Borst compression fitting. Radiopaque markers may be placedat different locations along the shaft 604, often near the balloon 606and/or stent 608, to help mark the proximal and distal ends of the stentor balloon, as well to facilitate alignment of the two catheters duringstent deployment, as discussed elsewhere in this specification.

The second catheter 630 includes an elongate shaft 632 with a radiallyexpandable balloon 640 disposed near a distal end of the elongate shaft632. A stent 642 having a proximal portion 622, a distal portion 614,and a side hole 620 is disposed over balloon 640. The distal portion 614is crimped to balloon 640 to prevent ejection during delivery, while theproximal portion 622 is partially crimped to balloon 640 so elongateshaft 604 may be slidably advanced or retracted under the proximalportion 622 of stent 642. The stent may preferably have a length thatmatches the working length of the balloon, or the stent length may beshorter than the balloon working length. At least a portion of balloon606, and stent 608 are distally offset relative to balloon 640 and stent642 so as to minimize profile of the device. In this embodiment thedistal stent 608 may be deployed in a main branch of the vessel and theother stent 642 may be deployed in a side branch of the vessel.Alternatively, the distal stent 608 may be deployed in a side branch ofa vessel and the other stent 642 may be deployed in the main branch of avessel. The second catheter 630 is a rapid exchange catheter (RX) havinga guidewire lumen 634 extending from the distal guidewire port 638 atthe distal end of the elongate shaft 632 to a proximal guidewire port636 which is closer to the distal port 638 than the proximal end of thecatheter shaft 632. The proximal guidewire port 636 is also unobstructedby the capture tube 624 and may be distal thereto. A connector 644,preferably a Luer connector is connected to the proximal end of theelongate shaft 632 and allows an Indeflator or other device to becoupled with an inflation lumen (not shown) in elongate shaft 632 forinflation of balloon 640. A portion of shaft 632 is disposed in thecentral channel 626 of the capture tube 624 and this helps keep the twocatheter shafts 604, 632 parallel and prevents tangling during deliveryand as shaft 604 is slidably advanced in the central channel 626.Compression fitting 625 may be used to lock elongate shafts 604, 632 inthe capture tube 624 to prevent axial movement. The compression fittingmay be a Tuohy-Borst fitting. Also, a portion of shaft 604 is disposedunder proximal portion 622 of stent 642. The first catheter 602 may beslidably advanced or retracted under the proximal portion 622 of stent642 so that the shaft 604 passes through the side hole 620 in stent 642.Radiopaque markers may be placed at different locations on the shaft632, often near the balloon 640 or stent 642, to help mark the proximaland distal ends of the stent or balloon, as well to facilitate alignmentof the two catheters during stent deployment, as discussed elsewhere inthis specification.

FIG. 7A shows a catheter system 700 having dual rapid exchange motherand daughter catheters so the end point of the capture tube ispreferably about 10 centimeters proximal from the rapid exchange port onthe distal most catheter. FIG. 7B more clearly illustrates the featuresof the catheter system 700 in FIG. 7A. The stent delivery system 700includes a first catheter 702, and a second catheter 730. The firstcatheter 702 includes an elongate shaft 704 with a radially expandableballoon 706 disposed near a distal end of the elongate shaft 704. Astent 708 having a proximal portion 722, a distal portion 714 and a sidehole 720 is disposed over the balloon 706. The distal portion 714 iscrimped to the balloon 706 to prevent ejection during delivery, whilethe proximal portion 722 is partially crimped to the balloon 706 so thesecond catheter 730 may be slidably advanced under the proximal portion722 of stent 708. The first catheter is a rapid exchange catheter (RX)having a guidewire lumen 712 extending from the distal guidewire port710 at the distal end of the elongate shaft 704 to a proximal guidewireport 711 which is closer to the distal port 710 than the proximal end ofthe catheter shaft 704. A connector 716 is coupled with the proximal endof the elongate shaft 704. The connector 716 is preferably a Luerconnector and this allows easy coupling with an Indeflator or otherdevice for inflation of the balloon 706. The first catheter 702 isdisposed in the central channel 726 of a capture tube 724. Centralchannel 726 is sized to fit both shafts 704, 732 and allow slidablemovement thereof. Shaft 704 is slidable in the central channel 726, orit may be locked with a locking collar 725 such as a Tuohy-Borstcompression fitting. Radiopaque markers may be placed at differentlocations along the shaft 704, often near the balloon 706 and/or stent708, to help mark the proximal and distal ends of the stent or balloon,as well to facilitate alignment of the two catheters during stentdeployment, as discussed elsewhere in this specification.

The second catheter 730 includes an elongate shaft 732 with a radiallyexpandable balloon 740 disposed near a distal end of the elongate shaft732. A stent 742 is disposed over balloon 740. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 742 is shorter than the working length of theballoon 740 so that a proximal portion of the balloon 740 isunconstrained by the stent 742 and this unconstrained portion of theballoon 740 may be slidably advanced or refracted through side hole 720and under proximal portion 722 of stent 708 as will be discussed below.Stent 742 is crimped to balloon 740 to prevent ejection during delivery.At least a portion of balloon 740, and stent 742 are distally offsetrelative to balloon 706 and stent 708 so as to minimize profile of thedevice. In this embodiment the distal stent 742 may be deployed in amain branch of the vessel and the other stent 708 may be deployed in aside branch of the vessel. Alternatively, the distal stent 742 may bedeployed in a side branch of a vessel and the other stent 708 may bedeployed in the main branch of a vessel. The second catheter 730 is arapid exchange catheter (RX) having a guidewire lumen 734 extending fromthe distal guidewire port 738 at the distal end of the elongate shaft732 to a proximal guidewire port 736 which is closer to the distal port738 than the proximal end of the catheter shaft 732. The proximalguidewire port 736 is also unobstructed by the capture tube 724 and maybe distal thereto. A connector 744, preferably a Luer connector isconnected to the proximal end of the elongate shaft 732 and allows anIndeflator or other device to be coupled with an inflation lumen (notshown) in elongate shaft 732 for inflation of balloon 740. A portion ofshaft 732 is disposed in the central channel 726 of the capture tube 724and this helps keep the two catheter shafts 704, 732 parallel andprevents tangling during delivery and as shaft 732 is slidably advancedin the central channel 726. Compression fitting 725 may be used to lockelongate shafts 704, 732 in the capture tube 724 to prevent axialmovement. The compression fitting may be a Tuohy-Borst fitting. Also,another portion of shaft 732 is disposed under proximal portion 722 ofstent 708. The second catheter 730 may also be slidably advanced orretracted under the proximal portion 722 of stent 708 so that the shaft732 passes through the side hole 720 in stent 708. Radiopaque markersmay be placed at different locations on the shaft 732, often near theballoon 740 or stent 742, to help mark the proximal and distal ends ofthe stent or balloon, as well to facilitate alignment of the twocatheters during stent deployment, as discussed elsewhere in thisspecification.

FIG. 8A embodies a catheter system 800 with dual over the wire designs,therefore the capture tube ending point ends preferably about 30centimeters proximal from the balloon portion of the most distalcatheter. FIG. 8B more clearly illustrates the features of the cathetersystem 800 in FIG. 8A. The stent delivery system 800 includes a firstcatheter 802, and a second catheter 830. The first catheter 802 includesan elongate shaft 804 with a radially expandable balloon 806 disposednear a distal end of the elongate shaft 804. A stent 808 having aproximal portion 822, a distal portion 814 and a side hole 820 isdisposed over the balloon 806. The distal portion 814 is crimped to theballoon 806 to prevent ejection during delivery, while the proximalportion 822 is partially crimped to the balloon 806 so the secondcatheter 830 may be slidably advanced under the proximal portion 822 ofstent 808. The first catheter is an over-the-wire (OTW) catheter havinga guidewire lumen 812 extending from the distal guidewire port 810 atthe distal end of the elongate shaft 804 to the proximal end of theelongate shaft 804 into Y-adapter 814 having a connector 816. Theconnector 816 is preferably a Luer connector and this allows easycoupling with a syringe or other device for lumen flushing or injectingcontrast media. When unconnected, the guidewire lumen 812 exits viaconnector 816. A second connector 818, also preferably a Luer connectorallows attachment of an Indeflator or other device to the catheter forinflation of the balloon 806 via an inflation lumen (not shown) in theelongate shaft 804. The first catheter 802 is disposed in the centralchannel 826 of a capture tube 824. Central channel 826 is sized to fitboth shafts 804, 832 and allow slidable movement thereof. Shaft 804 isslidable in the central channel 826, or it may be locked with a lockingcollar 825 such as a Tuohy-Borst compression fitting. Radiopaque markersmay be placed at different locations along the shaft 804, often near theballoon 806 and/or stent 808, to help mark the proximal and distal endsof the stent or balloon, as well to facilitate alignment of the twocatheters during stent deployment, as discussed elsewhere in thisspecification.

The second catheter 830 includes an elongate shaft 832 with a radiallyexpandable balloon 840 disposed near a distal end of the elongate shaft832. A stent 842 is disposed over balloon 840. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 842 is shorter than the working length of theballoon 840 so that a proximal portion of the balloon 840 isunconstrained by the stent 842 and this unconstrained portion of theballoon 840 may be slidably advanced or refracted through side hole 820and under proximal portion 822 of stent 808 as will be discussed below.Stent 842 is crimped to balloon 840 to prevent ejection during delivery.At least a portion of balloon 840, and stent 842 are distally offsetrelative to balloon 806 and stent 808 so as to minimize profile of thedevice. In this embodiment the distal stent 842 may be deployed in amain branch of the vessel and the other stent 808 may be deployed in aside branch of the vessel. Alternatively, the distal stent 842 may bedeployed in a side branch of a vessel and the other stent 808 may bedeployed in the main branch of a vessel. The second catheter 830 is anover-the-wire (OTW) catheter having a guidewire lumen 834 extending fromthe distal guidewire port 838 at the distal end of the elongate shaft832 to the proximal end of the elongate shaft 832 into Y-adapter 846having a connector 848. The connector 848 is preferably a Luer connectorand this allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 834 exits via connector 848. A second connector 844, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 840 via an inflationlumen (not shown) in the elongate shaft 832. A portion of shaft 832 isdisposed in the central channel 826 of the capture tube 824 and thishelps keep the two catheter shafts 804, 832 parallel and preventstangling during delivery and as shaft 832 is slidably advanced in thecentral channel 826. Compression fitting 825 may be used to lockelongate shafts 804, 832 in the capture tube 824 to prevent axialmovement. The compression fitting may be a Tuohy-Borst fitting. Also,another portion of shaft 832 is disposed under proximal portion 822 ofstent 808. The second catheter 830 may also be slidably advanced orretracted under the proximal portion 822 of stent 808 so that the shaft832 passes through the side hole 820 in stent 808. Radiopaque markersmay be placed at different locations on the shaft 832, often near theballoon 840 or stent 842, to help mark the proximal and distal ends ofthe stent or balloon, as well to facilitate alignment of the twocatheters during stent deployment, as discussed elsewhere in thisspecification.

FIGS. 9A, 10A, 11A, and 12A illustrate a removable capture tube that isfitted over the dual catheters as described above but the capture tubehas a polymer appendage. Once the operator has the catheter systemplaced near the bifurcation the operator can grab hold of the polymerappendage and pull the capture tube off of the catheters.

FIG. 9A illustrates a catheter system 900 having a distal daughtercatheter with a rapid exchange configuration and a proximal mothercatheter with an over the wire configuration. FIG. 9B more clearlyillustrates the features of the catheter system 900 seen in FIG. 9A. Thestent delivery system 900 includes a first catheter 902, and a secondcatheter 930. The first catheter 902 includes an elongate shaft 904 witha radially expandable balloon 906 disposed near a distal end of theelongate shaft 904. A stent 908 having a proximal portion 922, a distalportion 914 and a side hole 920 is disposed over the balloon 906. Thedistal portion 914 is crimped to the balloon 906 to prevent ejectionduring delivery, while the proximal portion 922 is partially crimped tothe balloon 906 so the second catheter 930 may be slidably advancedunder the proximal portion 922 of stent 908. The first catheter is anover-the-wire (OTW) catheter having a guidewire lumen 912 extending fromthe distal guidewire port 910 at the distal end of the elongate shaft904 to the proximal end of the elongate shaft 904 into Y-adapter 914having a connector 916. The connector 916 is preferably a Luer connectorand this allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 912 exits via connector 916. A second connector 918, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 906 via an inflationlumen (not shown) in the elongate shaft 904. The first catheter 902 isdisposed in the central channel 926 of a capture tube 924 having aperforated region 945 along its longitudinal length. Central channel 926is sized to fit both shafts 904, 932 and allow slidable movementthereof. Shaft 904 is slidable in the central channel 926, or it may belocked with a locking collar 925 such as a Tuohy-Borst compressionfitting. Radiopaque markers may be placed at different locations alongthe shaft 904, often near the balloon 906 and/or stent 908, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification. The perforated region 945along the capture tube 924 allows the capture tube to be easily peeledaway from both catheter shafts 904, 932 once the catheters have beenproperly positioned and when no longer needed.

The second catheter 930 includes an elongate shaft 932 with a radiallyexpandable balloon 940 disposed near a distal end of the elongate shaft932. A stent 942 is disposed over balloon 940. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 942 is shorter than the working length of theballoon 940 so that a proximal portion of the balloon 940 isunconstrained by the stent 942 and this unconstrained portion of theballoon 940 may be slidably advanced or refracted through side hole 920and under proximal portion 922 of stent 908 as will be discussed below.Stent 942 is crimped to balloon 940 to prevent ejection during delivery.At least a portion of balloon 940, and stent 942 are distally offsetrelative to balloon 906 and stent 908 so as to minimize profile of thedevice. In this embodiment the distal stent 942 may be deployed in amain branch of the vessel and the other stent 908 may be deployed in aside branch of the vessel. Alternatively, the distal stent 942 may bedeployed in a side branch of a vessel and the other stent 908 may bedeployed in the main branch of a vessel. The second catheter 930 is arapid exchange catheter (RX) having a guidewire lumen 934 extending fromthe distal guidewire port 938 at the distal end of the elongate shaft932 to a proximal guidewire port 936 which is closer to the distal port938 than the proximal end of the catheter shaft 932. The proximalguidewire port 936 is also unobstructed by the capture tube 924 and maybe distal thereto. A connector 944, preferably a Luer connector isconnected to the proximal end of the elongate shaft 932 and allows anIndeflator or other device to be coupled with an inflation lumen (notshown) in elongate shaft 932 for inflation of balloon 940. A portion ofshaft 932 is disposed in the central channel 926 of the capture tube 924and this helps keep the two catheter shafts 904, 932 parallel andprevents tangling during delivery and as shaft 932 is slidably advancedin the central channel 926. Compression fitting 925 may be used to lockelongate shafts 904, 932 in the capture tube 924 to prevent axialmovement. The compression fitting may be a Tuohy-Borst fitting. Also,another portion of shaft 932 is disposed under proximal portion 922 ofstent 908. The second catheter 930 may also be slidably advanced orretracted under the proximal portion 922 of stent 908 so that the shaft932 passes through the side hole 920 in stent 908. Capture tube 924 maybe peeled away from shaft 932 by severing the perforated region 945.Radiopaque markers may be placed at different locations on the shaft932, often near the balloon 940 or stent 942, to help mark the proximaland distal ends of the stent or balloon, as well to facilitate alignmentof the two catheters during stent deployment, as discussed elsewhere inthis specification.

FIG. 10A illustrates a catheter system 1000 having a distal daughtercatheter with an over the wire design and a proximal mother catheterwith a rapid exchange design. FIG. 10B more clearly illustrates thefeatures of the catheter system 1000 in FIG. 10A. The stent deliverysystem 1000 includes a first catheter 1002, and a second catheter 1030.The first catheter 1002 includes an elongate shaft 1004 with a radiallyexpandable balloon 1006 disposed near a distal end of the elongate shaft1004, and a stent 1008 disposed over the balloon 1006. The stent 1008may be the same length as the working length of the balloon 1008, or itmay be shorter. In preferred embodiments, the stent 1008 is shorter thanthe working length of balloon 1006 such that a proximal portion ofballoon 1006 remains unconstrained by stent 1008. The proximal portionof balloon 1006 may be slidably advanced and retracted under stent 1042via side hole 1020. Stent 1008 is crimped to the balloon 1006 to preventejection during delivery. The first catheter is an over-the-wire (OTW)catheter having a guidewire lumen 1012 extending from the distalguidewire port 1010 at the distal end of the elongate shaft 1004 to theproximal end of the elongate shaft 1004 into Y-adapter 1014 having aconnector 1016. The connector 1016 is preferably a Luer connector andthis allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 1012 exits via connector 1016. A second connector 1018, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 1006 via aninflation lumen (not shown) in the elongate shaft 1004. The firstcatheter 1002 is disposed in the central channel 1026 of a capture tube1024 having perforated region 1045. Central channel 1026 is sized to fitboth shafts 1004, 1032 and allow slidable movement thereof. Shaft 1004is slidable in the central channel 1026, or it may be locked with alocking collar 1025 such as a Tuohy-Borst compression fitting.Radiopaque markers may be placed at different locations along the shaft1004, often near the balloon 1006 and/or stent 1008, to help mark theproximal and distal ends of the stent or balloon, as well to facilitatealignment of the two catheters during stent deployment, as discussedelsewhere in this specification. The perforated region 1045 along thecapture tube 1024 allows the capture tube to be easily peeled away fromboth catheter shafts 1004, 1032 once the catheters have been properlypositioned and when no longer needed.

The second catheter 1030 includes an elongate shaft 1032 with a radiallyexpandable balloon 1040 disposed near a distal end of the elongate shaft1032. A stent 1042 having a proximal portion 1022, a distal portion1014, and a side hole 1020 is disposed over balloon 1040. The distalportion 1014 is crimped to balloon 1040 to prevent ejection duringdelivery, while the proximal portion 1022 is partially crimped toballoon 1040 so elongate shaft 1004 may be slidably advanced orretracted under the proximal portion 1022 of stent 1042. The stent maypreferably have a length that matches the working length of the balloon,or the stent length may be shorter than the balloon working length. Atleast a portion of balloon 1006, and stent 1008 are distally offsetrelative to balloon 1040 and stent 1042 so as to minimize profile of thedevice. In this embodiment the distal stent 1008 may be deployed in amain branch of the vessel and the other stent 1042 may be deployed in aside branch of the vessel. Alternatively, the distal stent 1008 may bedeployed in a side branch of a vessel and the other stent 1042 may bedeployed in the main branch of a vessel. The second catheter 1030 is arapid exchange catheter (RX) having a guidewire lumen 1034 extendingfrom the distal guidewire port 1038 at the distal end of the elongateshaft 1032 to a proximal guidewire port 1036 which is closer to thedistal port 1038 than the proximal end of the catheter shaft 1032. Theproximal guidewire port 1036 is also unobstructed by the capture tube1024 and may be distal thereto. A connector 1044, preferably a Luerconnector is connected to the proximal end of the elongate shaft 1032and allows an Indeflator or other device to be coupled with an inflationlumen (not shown) in elongate shaft 1032 for inflation of balloon 1040.A portion of shaft 1032 is disposed in the central channel 1026 of thecapture tube 1024 and this helps keep the two catheter shafts 1004, 1032parallel and prevents tangling during delivery and as shaft 1032 isslidably advanced in the central channel 1026. Compression fitting 1025may be used to lock elongate shafts 1004, 1032 in the capture tube 1024to prevent axial movement. The compression fitting may be a Tuohy-Borstfitting. Also, a portion of shaft 1004 is disposed under proximalportion 1022 of stent 1042. The first catheter 1002 may be slidablyadvanced or retracted under the proximal portion 1022 of stent 1042 sothat the shaft 1004 passes through the side hole 1020 in stent 1042.Capture tube 1024 may be peeled away from shaft 1032 by severing theperforated region 1045. Radiopaque markers may be placed at differentlocations on the shaft 1032, often near the balloon 1040 or stent 1042,to help mark the proximal and distal ends of the stent or balloon, aswell to facilitate alignment of the two catheters during stentdeployment, as discussed elsewhere in this specification.

FIG. 11A illustrates a catheter system 1100 having dual rapid exchangedesign with a removable capture tube. FIG. 11B more clearly illustratesthe features of the catheter system 1100 in FIG. 11A. The stent deliverysystem 1100 includes a first catheter 1102, and a second catheter 1130.The first catheter 1102 includes an elongate shaft 1104 with a radiallyexpandable balloon 1106 disposed near a distal end of the elongate shaft1104. A stent 1108 having a proximal portion 1122, a distal portion 1114and a side hole 1120 is disposed over the balloon 1106. The distalportion 1114 is crimped to the balloon 1106 to prevent ejection duringdelivery, while the proximal portion 1122 is partially crimped to theballoon 1106 so the second catheter 1130 may be slidably advanced underthe proximal portion 1122 of stent 1108. The first catheter is a rapidexchange catheter (RX) having a guidewire lumen 1112 extending from thedistal guidewire port 1110 at the distal end of the elongate shaft 1104to a proximal guidewire port 1111 which is closer to the distal port1110 than the proximal end of the catheter shaft 1104. A connector 1116is coupled with the proximal end of the elongate shaft 1104. Theconnector 1116 is preferably a Luer connector and this allows easycoupling with an Indeflator or other device for inflation of the balloon1106. The first catheter 1102 is disposed in the central channel 1126 ofa capture tubel 124 having a perforated region 1145. Central channel1126 is sized to fit both shafts 1104, 1132 and allow slidable movementthereof. Shaft 1104 is slidable in the central channel 1126, or it maybe locked with a locking collar 1125 such as a Tuohy-Borst compressionfitting. Radiopaque markers may be placed at different locations alongthe shaft 1104, often near the balloon 1106 and/or stent 1108, to helpmark the proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification. The perforated region 1145along the capture tube 1124 allows the capture tube to be easily peeledaway from both catheter shafts 1104, 1132 once the catheters have beenproperly positioned and when no longer needed.

The second catheter 1130 includes an elongate shaft 1132 with a radiallyexpandable balloon 1140 disposed near a distal end of the elongate shaft1132. A stent 1142 is disposed over balloon 1140. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1142 is shorter than the working length of theballoon 1140 so that a proximal portion of the balloon 1140 isunconstrained by the stent 1142 and this unconstrained portion of theballoon 1140 may be slidably advanced or retracted through side hole1120 and under proximal portion 1122 of stent 1108 as will be discussedbelow. Stent 1142 is crimped to balloon 1140 to prevent ejection duringdelivery. At least a portion of balloon 1140, and stent 1142 aredistally offset relative to balloon 1106 and stent 1108 so as tominimize profile of the device. In this embodiment the distal stent 1142may be deployed in a main branch of the vessel and the other stent 1108may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1142 may be deployed in a side branch of a vessel and theother stent 1108 may be deployed in the main branch of a vessel. Thesecond catheter 1130 is a rapid exchange catheter (RX) having aguidewire lumen 1134 extending from the distal guidewire port 1138 atthe distal end of the elongate shaft 1132 to a proximal guidewire port1136 which is closer to the distal port 1138 than the proximal end ofthe catheter shaft 1132. The proximal guidewire port 1136 is alsounobstructed by the capture tube 1124 and may be distal thereto. Aconnector 1144, preferably a Luer connector is connected to the proximalend of the elongate shaft 1132 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 1132for inflation of balloon 1140. A portion of shaft 1132 is disposed inthe central channel 1126 of the capture tube 1124 and this helps keepthe two catheter shafts 1104, 1132 parallel and prevents tangling duringdelivery and as shaft 1132 is slidably advanced in the central channel1126. Compression fitting 1125 may be used to lock elongate shafts 1104,1132 in the capture tube 1124 to prevent axial movement. The compressionfitting may be a Tuohy-Borst fitting. Also, another portion of shaft1132 is disposed under proximal portion 1122 of stent 1108. The secondcatheter 1130 may also be slidably advanced or retracted under theproximal portion 1122 of stent 1108 so that the shaft 1132 passesthrough the side hole 1120 in stent 1108. Capture tube 1124 may bepeeled away from shaft 1132 by severing the perforated region 1145.Radiopaque markers may be placed at different locations on the shaft1132, often near the balloon 1140 or stent 1142, to help mark theproximal and distal ends of the stent or balloon, as well to facilitatealignment of the two catheters during stent deployment, as discussedelsewhere in this specification.

FIG. 12A illustrates a catheter system 1200 having dual over the wiredesign with a removable capture tube. FIG. 12B more clearly illustratesthe features of the catheter system 1200 in FIG. 12A. The stent deliverysystem 1200 includes a first catheter 1202, and a second catheter 1230.The first catheter 1202 includes an elongate shaft 1204 with a radiallyexpandable balloon 1206 disposed near a distal end of the elongate shaft1204. A stent 1208 having a proximal portion 1222, a distal portion 1214and a side hole 1220 is disposed over the balloon 1206. The distalportion 1214 is crimped to the balloon 1206 to prevent ejection duringdelivery, while the proximal portion 1222 is partially crimped to theballoon 1206 so the second catheter 1230 may be slidably advanced underthe proximal portion 1222 of stent 1208. The first catheter is anover-the-wire (OTW) catheter having a guidewire lumen 1212 extendingfrom the distal guidewire port 1210 at the distal end of the elongateshaft 1204 to the proximal end of the elongate shaft 1204 into Y-adapter1214 having a connector 1216. The connector 1216 is preferably a Luerconnector and this allows easy coupling with a syringe or other devicefor lumen flushing or injecting contrast media. When unconnected, theguidewire lumen 1212 exits via connector 1216. A second connector 1218,also preferably a Luer connector allows attachment of an Indeflator orother device to the catheter for inflation of the balloon 1206 via aninflation lumen (not shown) in the elongate shaft 1204. The firstcatheter 1202 is disposed in the central channel 1226 of a capture tube1224 having a perforated region 1245. Central channel 1226 is sized tofit both shafts 1204, 1232 and allow slidable movement thereof. Shaft1204 is slidable in the central channel 1226, or it may be locked with alocking collar 1225 such as a Tuohy-Borst compression fitting.Radiopaque markers may be placed at different locations along the shaft1204, often near the balloon 1206 and/or stent 1208, to help mark theproximal and distal ends of the stent or balloon, as well to facilitatealignment of the two catheters during stent deployment, as discussedelsewhere in this specification. The perforated region 1245 along thecapture tube 1224 allows the capture tube to be easily peeled away fromboth catheter shafts 1204, 1232 once the catheters have been properlypositioned and when no longer needed.

The second catheter 1230 includes an elongate shaft 1232 with a radiallyexpandable balloon 1240 disposed near a distal end of the elongate shaft1232. A stent 1242 is disposed over balloon 1240. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1242 is shorter than the working length of theballoon 1240 so that a proximal portion of the balloon 1240 isunconstrained by the stent 1242 and this unconstrained portion of theballoon 1240 may be slidably advanced or retracted through side hole1220 and under proximal portion 1222 of stent 1208 as will be discussedbelow. Stent 1242 is crimped to balloon 1240 to prevent ejection duringdelivery. At least a portion of balloon 1240, and stent 1242 aredistally offset relative to balloon 1206 and stent 1208 so as tominimize profile of the device. In this embodiment the distal stent 1242may be deployed in a main branch of the vessel and the other stent 1208may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1242 may be deployed in a side branch of a vessel and theother stent 1208 may be deployed in the main branch of a vessel. Thesecond catheter 1230 is an over-the-wire (OTW) catheter having aguidewire lumen 1234 extending from the distal guidewire port 1238 atthe distal end of the elongate shaft 1232 to the proximal end of theelongate shaft 1232 into Y-adapter 1246 having a connector 1248. Theconnector 1248 is preferably a Luer connector and this allows easycoupling with a syringe or other device for lumen flushing or injectingcontrast media. When unconnected, the guidewire lumen 1234 exits viaconnector 1248. A second connector 1244, also preferably a Luerconnector allows attachment of an Indeflator or other device to thecatheter for inflation of the balloon 1240 via an inflation lumen (notshown) in the elongate shaft 1232. A portion of shaft 1232 is disposedin the central channel 1226 of the capture tube 1224 and this helps keepthe two catheter shafts 1204, 1232 parallel and prevents tangling duringdelivery and as shaft 1232 is slidably advanced in the central channel1226. Compression fitting 1225 may be used to lock elongate shafts 1204,1232 in the capture tube 1224 to prevent axial movement. The compressionfitting may be a Tuohy-Borst fitting. Also, another portion of shaft1232 is disposed under proximal portion 1222 of stent 1208. The secondcatheter 1230 may also be slidably advanced or retracted under theproximal portion 1222 of stent 1208 so that the shaft 1232 passesthrough the side hole 1220 in stent 1208. Capture tube 1224 may bepeeled away from shaft 1232 by severing the perforated region 1245.Radiopaque markers may be placed at different locations on the shaft1232, often near the balloon 1240 or stent 1242, to help mark theproximal and distal ends of the stent or balloon, as well to facilitatealignment of the two catheters during stent deployment, as discussedelsewhere in this specification.

FIGS. 13A, 14A, 15A, and 16A illustrates a zipper that allows onecatheter to snap in to the other catheter. The zipper is essentially agroove that forms a concave receiving cross section and is carved into acatheter's outer surface in a straight line. The groove can be a singlegroove over a certain portion of a catheter or it can run from end toend. Alternatively, the catheter can have a series of short grooves of 1to 10 centimeters in length that run the length of the catheter or onlya certain portion. Full length end to end zippers will have reducedprofile and reduced friction with the vessel. The resulting groove canreceive another catheter and prevent the catheters from dislodging whilethe operator is advancing the catheters to the bifurcation. Once at thesite the operator can still slidably move the catheters forward and backrelative to each other. Mother catheters that utilize the groove canhave fully crimped stents as described in several of the embodimentsabove; however, it is possible to allow operators to choose anycommercially available catheter with or without a stent and mount thecommercially available catheter via the zipper. The mother catheterswith an empty zipper would have a mother stent fully crimped on thedistal balloon portion. After loading the commercially availablecatheter the operator would have to crimp the proximal portion of themother stent in situ prior to beginning the clinical procedure. Thisoption may be extremely valuable to operators who can reduce their totalinventory of catheters but have more options for treating bifurcatedlesions.

FIG. 13A illustrates a catheter system 1300 having a distal daughtercatheter with an over the wire design and a proximal mother catheterwith a rapid exchange design and a short zipper. FIG. 13B more clearlyillustrates the features of the catheter system 1300 in FIG. 13A. Thestent delivery system 1300 includes a first catheter 1302, and a secondcatheter 1330. The first catheter 1302 includes an elongate shaft 1304with a radially expandable balloon 1306 disposed near a distal end ofthe elongate shaft 1304. A stent 1308 having a proximal portion 1322, adistal portion 1314 and a side hole 1320 is disposed over the balloon1306. The distal portion 1314 is crimped to the balloon 1306 to preventejection during delivery, while the proximal portion 1322 is partiallycrimped to the balloon 1306 so the second catheter 1330 may be slidablyadvanced under the proximal portion 1322 of stent 1308. The firstcatheter is an over-the-wire (OTW) catheter having a guidewire lumen1312 extending from the distal guidewire port 1310 at the distal end ofthe elongate shaft 1304 to the proximal end of the elongate shaft 1304into Y-adapter 1314 having a connector 1316. The connector 1316 ispreferably a Luer connector and this allows easy coupling with a syringeor other device for lumen flushing or injecting contrast media. Whenunconnected, the guidewire lumen 1312 exits via connector 1316. A secondconnector 1318, also preferably a Luer connector allows attachment of anIndeflator or other device to the catheter for inflation of the balloon1306 via an inflation lumen (not shown) in the elongate shaft 1304. Thefirst catheter 1302 also includes a zipper or snap fitting 1324 coupledto the elongate shaft 1304. The snap fit tube 1324 may be coextrudedwith the first shaft 1304, or it may be bonded or otherwise attachedthereto using techniques known to those skilled in the art. The snap fit1324 may alternatively be coupled with the other shaft 1332. The snapfitting 1324 includes a central channel 1326 extending therethrough andis sized to slidably receive a portion of the second catheter 1330. Anelongate slot 1345 extends along the entire length of the snap fitting1324 and is sized so that shaft 1336 may snapped into the centralchannel 1326. FIG. 13C illustrates a partial cross-section of FIG. 13Btaken along the line C-C and shows shaft 1304 with the snap fitting1324. Radiopaque markers may be placed at different locations along theshaft 1304, often near the balloon 1306 and/or stent 1308, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

The second catheter 1330 includes an elongate shaft 1332 with a radiallyexpandable balloon 1340 disposed near a distal end of the elongate shaft1332. A stent 1342 is disposed over balloon 1340. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1342 is shorter than the working length of theballoon 1340 so that a proximal portion of the balloon 1340 isunconstrained by the stent 1342 and this unconstrained portion of theballoon 1340 may be slidably advanced or retracted through side hole1320 and under proximal portion 1322 of stent 1308 as will be discussedbelow. Stent 1342 is crimped to balloon 1340 to prevent ejection duringdelivery. At least a portion of balloon 1340, and stent 1342 aredistally offset relative to balloon 1306 and stent 1308 so as tominimize profile of the device. In this embodiment the distal stent 1342may be deployed in a main branch of the vessel and the other stent 1308may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1342 may be deployed in a side branch of a vessel and theother stent 1308 may be deployed in the main branch of a vessel. Thesecond catheter 1330 is a rapid exchange catheter (RX) having aguidewire lumen 1334 extending from the distal guidewire port 1338 atthe distal end of the elongate shaft 1332 to a proximal guidewire port1336 which is closer to the distal port 1338 than the proximal end ofthe catheter shaft 1332. The proximal guidewire port 1336 is alsounobstructed by the snap fitting 1324 and preferably proximal thereto. Aconnector 1344, preferably a Luer connector is connected to the proximalend of the elongate shaft 1332 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 1332for inflation of balloon 1340. A portion of shaft 1332 is snapped intothe central channel 1326 of the snap fitting 1324 via slit 1345, andthus shaft 1332 may slide in channel 1326. This helps keep the twocatheter shafts 1304, 1332 parallel and prevents tangling duringdelivery and as shaft 1332 is slidably advanced or retracted relative toshaft 1304. Also, another portion of shaft 1332 is disposed underproximal portion 1322 of stent 1308. The second catheter 1330 may alsobe slidably advanced or refracted under the proximal portion 1322 ofstent 1308 so that the shaft 1332 passes through the side hole 1320 instent 1308. Radiopaque markers may be placed at different locations onthe shaft 1332, often near the balloon 1340 or stent 1342, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIG. 14A illustrates a catheter system 1400 having a proximal mothercatheter with a rapid exchange configuration and a distal daughtercatheter having an over-the-wire configuration and a short zipper orsnap fitting. FIG. 14B more clearly illustrates the features of thecatheter system 1400 in FIG. 14A. The stent delivery system 1400includes a first catheter 1402, and a second catheter 1430. The firstcatheter 1402 includes an elongate shaft 1404 with a radially expandableballoon 1406 disposed near a distal end of the elongate shaft 1404, anda stent 1408 disposed over the balloon 1406. The stent 1408 may be thesame length as the working length of the balloon 1408, or it may beshorter. In preferred embodiments, the stent 1408 is shorter than theworking length of balloon 1406 such that a proximal portion of balloon1406 remains unconstrained by stent 1408. The proximal portion ofballoon 1406 may be slidably advanced and retracted under stent 1442 viaside hole 1420. Stent 1408 is crimped to the balloon 1406 to preventejection during delivery. The first catheter is an over-the-wire (OTW)catheter having a guidewire lumen 1412 extending from the distalguidewire port 1410 at the distal end of the elongate shaft 1404 to theproximal end of the elongate shaft 1404 into Y-adapter 1414 having aconnector 1416. The connector 1416 is preferably a Luer connector andthis allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 1412 exits via connector 1416. A second connector 1418, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 1406 via aninflation lumen (not shown) in the elongate shaft 1404. The firstcatheter 1402 also includes a zipper or snap fitting 1424 coupled to theelongate shaft 1404. The snap fit tube 1424 may be coextruded with thefirst shaft 1404, or it may be bonded or otherwise attached theretousing techniques known to those skilled in the art. The snap fit 1424may alternatively be coupled with the other shaft 1432. The snap fitting1424 includes a central channel 1426 extending therethrough and is sizedto slidably receive a portion of the second catheter 1430. An elongateslot 1445 extends along the entire length of the snap fitting 1424 andis sized so that shaft 1436 may snapped into the central channel 1426.FIG. 14C illustrates a partial cross-section of FIG. 14B taken along theline C-C and shows shaft 1404 with the snap fitting 1424. Radiopaquemarkers may be placed at different locations along the shaft 1404, oftennear the balloon 1406 and/or stent 1408, to help mark the proximal anddistal ends of the stent or balloon, as well to facilitate alignment ofthe two catheters during stent deployment, as discussed elsewhere inthis specification.

The second catheter 1430 includes an elongate shaft 1432 with a radiallyexpandable balloon 1440 disposed near a distal end of the elongate shaft1432. A stent 1442 having a proximal portion 1422, a distal portion1414, and a side hole 1420 is disposed over balloon 1440. The distalportion 1414 is crimped to balloon 1440 to prevent ejection duringdelivery, while the proximal portion 1422 is partially crimped toballoon 1440 so elongate shaft 1404 may be slidably advanced orretracted under the proximal portion 1422 of stent 1442. The stent maypreferably have a length that matches the working length of the balloon,or the stent length may be shorter than the balloon working length. Atleast a portion of balloon 1406, and stent 1408 are distally offsetrelative to balloon 1440 and stent 1442 so as to minimize profile of thedevice. In this embodiment the distal stent 1408 may be deployed in amain branch of the vessel and the other stent 1442 may be deployed in aside branch of the vessel. Alternatively, the distal stent 1408 may bedeployed in a side branch of a vessel and the other stent 1442 may bedeployed in the main branch of a vessel. The second catheter 1430 is arapid exchange catheter (RX) having a guidewire lumen 1434 extendingfrom the distal guidewire port 1438 at the distal end of the elongateshaft 1432 to a proximal guidewire port 1436 which is closer to thedistal port 1438 than the proximal end of the catheter shaft 1432. Theproximal guidewire port 1436 is also unobstructed by the snap fitting1424 and preferably proximal thereto. A connector 1444, preferably aLuer connector is connected to the proximal end of the elongate shaft1432 and allows an Indeflator or other device to be coupled with aninflation lumen (not shown) in elongate shaft 1432 for inflation ofballoon 1440. A portion of shaft 1432 is snapped into the centralchannel 1426 of the snap fitting 1424 via slit 1445, and thus shaft 1432may slide in channel 1426. This helps keep the two catheter shafts 1404,1432 parallel and prevents tangling during delivery and as shaft 1432 isslidably advanced or retracted relative to shaft 1404. Also, a portionof shaft 1404 is disposed under proximal portion 1422 of stent 1442. Thefirst catheter 1402 may be slidably advanced or retracted under theproximal portion 1422 of stent 1442 so that the shaft 1404 passesthrough the side hole 1420 in stent 1442. Radiopaque markers may beplaced at different locations on the shaft 1432, often near the balloon1440 or stent 1442, to help mark the proximal and distal ends of thestent or balloon, as well to facilitate alignment of the two cathetersduring stent deployment, as discussed elsewhere in this specification.

FIG. 15A illustrates a catheter system 1500 having dual rapid exchangedesign with a short zipper or snap fitting. FIG. 15B more clearlyillustrates the features of the catheter system 1500 in FIG. 15A. Thestent delivery system 1500 includes a first catheter 1502, and a secondcatheter 1530. The first catheter 1502 includes an elongate shaft 1504with a radially expandable balloon 1506 disposed near a distal end ofthe elongate shaft 1504. A stent 1508 having a proximal portion 1522, adistal portion 1514 and a side hole 1520 is disposed over the balloon1506. The distal portion 1514 is crimped to the balloon 1506 to preventejection during delivery, while the proximal portion 1522 is partiallycrimped to the balloon 1506 so the second catheter 1530 may be slidablyadvanced under the proximal portion 1522 of stent 1508. The firstcatheter is a rapid exchange catheter (RX) having a guidewire lumen 1512extending from the distal guidewire port 1510 at the distal end of theelongate shaft 1504 to a proximal guidewire port 1511 which is closer tothe distal port 1510 than the proximal end of the catheter shaft 1504. Aconnector 1516 is coupled with the proximal end of the elongate shaft1504. The connector 1516 is preferably a Luer connector and this allowseasy coupling with an Indeflator or other device for inflation of theballoon 1506. The first catheter 1502 also includes a zipper or snapfitting 1524 coupled to the elongate shaft 1504. The snap fit tube 1524may be coextruded with the first shaft 1504, or it may be bonded orotherwise attached thereto using techniques known to those skilled inthe art. The snap fit 1524 may alternatively be coupled with the othershaft 1532. The snap fitting 1524 includes a central channel 1526extending therethrough and is sized to slidably receive a portion of thesecond catheter 1530. An elongate slot 1545 extends along the entirelength of the snap fitting 1524 and is sized so that shaft 1536 maysnapped into the central channel 1526. FIG. 15C illustrates a partialcross-section of FIG. 15B taken along the line C-C and shows shaft 1504with the snap fitting 1524. Radiopaque markers may be placed atdifferent locations along the shaft 1504, often near the balloon 1506and/or stent 1508, to help mark the proximal and distal ends of thestent or balloon, as well to facilitate alignment of the two cathetersduring stent deployment, as discussed elsewhere in this specification.

The second catheter 1530 includes an elongate shaft 1532 with a radiallyexpandable balloon 1540 disposed near a distal end of the elongate shaft1532. A stent 1542 is disposed over balloon 1540. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1542 is shorter than the working length of theballoon 1540 so that a proximal portion of the balloon 1540 isunconstrained by the stent 1542 and this unconstrained portion of theballoon 1540 may be slidably advanced or retracted through side hole1520 and under proximal portion 1522 of stent 1508 as will be discussedbelow. Stent 1542 is crimped to balloon 1540 to prevent ejection duringdelivery. At least a portion of balloon 1540, and stent 1542 aredistally offset relative to balloon 1506 and stent 1508 so as tominimize profile of the device. In this embodiment the distal stent 1542may be deployed in a main branch of the vessel and the other stent 1508may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1542 may be deployed in a side branch of a vessel and theother stent 1508 may be deployed in the main branch of a vessel. Thesecond catheter 1530 is a rapid exchange catheter (RX) having aguidewire lumen 1534 extending from the distal guidewire port 1538 atthe distal end of the elongate shaft 1532 to a proximal guidewire port1536 which is closer to the distal port 1538 than the proximal end ofthe catheter shaft 1532. The proximal guidewire port 1536 is alsounobstructed by the snap fitting 1524 and may be distal thereto. Aconnector 1544, preferably a Luer connector is connected to the proximalend of the elongate shaft 1532 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 1532for inflation of balloon 1540. A portion of shaft 1532 is snapped intothe central channel 1526 of the snap fitting 1524 via slit 1545, andthus shaft 1532 may slide in channel 1526. This helps keep the twocatheter shafts 1504, 1532 parallel and prevents tangling duringdelivery and as shaft 1532 is slidably advanced or retracted relative toshaft 1504. Also, another portion of shaft 1532 is disposed underproximal portion 1522 of stent 1508. The second catheter 1530 may alsobe slidably advanced or retracted under the proximal portion 1522 ofstent 1508 so that the shaft 1532 passes through the side hole 1520 instent 1508. Radiopaque markers may be placed at different locations onthe shaft 1532, often near the balloon 1540 or stent 1542, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIG. 16A illustrates a catheter system 1600 having a dual over the wiredesign with a short zipper or snap fitting. FIG. 16B more clearlyillustrates the features of the catheter system 1600 in FIG. 16A. Thestent delivery system 1600 includes a first catheter 1602, and a secondcatheter 1630. The first catheter 1602 includes an elongate shaft 1604with a radially expandable balloon 1606 disposed near a distal end ofthe elongate shaft 1604. A stent 1608 having a proximal portion 1622, adistal portion 1614 and a side hole 1620 is disposed over the balloon1606. The distal portion 1614 is crimped to the balloon 1606 to preventejection during delivery, while the proximal portion 1622 is partiallycrimped to the balloon 1606 so the second catheter 1630 may be slidablyadvanced under the proximal portion 1622 of stent 1608. The firstcatheter is an over-the-wire (OTW) catheter having a guidewire lumen1612 extending from the distal guidewire port 1610 at the distal end ofthe elongate shaft 1604 to the proximal end of the elongate shaft 1604into Y-adapter 1614 having a connector 1616. The connector 1616 ispreferably a Luer connector and this allows easy coupling with a syringeor other device for lumen flushing or injecting contrast media. Whenunconnected, the guidewire lumen 1612 exits via connector 1616. A secondconnector 1618, also preferably a Luer connector allows attachment of anIndeflator or other device to the catheter for inflation of the balloon1606 via an inflation lumen (not shown) in the elongate shaft 1604. Thefirst catheter 1602 also includes a zipper or snap fitting 1624 coupledto the elongate shaft 1604. The snap fit tube 1624 may be coextrudedwith the first shaft 1604, or it may be bonded or otherwise attachedthereto using techniques known to those skilled in the art. The snap fit1624 may alternatively be coupled with the other shaft 1632. The snapfitting 1624 includes a central channel 1626 extending therethrough andis sized to slidably receive a portion of the second catheter 1630. Anelongate slot 1645 extends along the entire length of the snap fitting1624 and is sized so that shaft 1636 may snapped into the centralchannel 1626. FIG. 16C illustrates a partial cross-section of FIG. 16Btaken along the line C-C and shows shaft 1604 with the snap fitting1624. Radiopaque markers may be placed at different locations along theshaft 1604, often near the balloon 1606 and/or stent 1608, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

The second catheter 1630 includes an elongate shaft 1632 with a radiallyexpandable balloon 1640 disposed near a distal end of the elongate shaft1632. A stent 1642 is disposed over balloon 1640. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1642 is shorter than the working length of theballoon 1640 so that a proximal portion of the balloon 1640 isunconstrained by the stent 1642 and this unconstrained portion of theballoon 1640 may be slidably advanced or retracted through side hole1620 and under proximal portion 1622 of stent 1608 as will be discussedbelow. Stent 1642 is crimped to balloon 1640 to prevent ejection duringdelivery. At least a portion of balloon 1640, and stent 1642 aredistally offset relative to balloon 1606 and stent 1608 so as tominimize profile of the device. In this embodiment the distal stent 1642may be deployed in a main branch of the vessel and the other stent 1608may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1642 may be deployed in a side branch of a vessel and theother stent 1608 may be deployed in the main branch of a vessel. Thesecond catheter 1630 is an over-the-wire (OTW) catheter having aguidewire lumen 1634 extending from the distal guidewire port 1638 atthe distal end of the elongate shaft 1632 to the proximal end of theelongate shaft 1632 into Y-adapter 1646 having a connector 1648. Theconnector 1648 is preferably a Luer connector and this allows easycoupling with a syringe or other device for lumen flushing or injectingcontrast media. When unconnected, the guidewire lumen 1634 exits viaconnector 1648. A second connector 1644, also preferably a Luerconnector allows attachment of an Indeflator or other device to thecatheter for inflation of the balloon 1640 via an inflation lumen (notshown) in the elongate shaft 1632. A portion of shaft 1632 is snappedinto the central channel 1626 of the snap fitting 1624 via slit 1645,and thus shaft 1632 may slide in channel 1626. This helps keep the twocatheter shafts 1604, 1632 parallel and prevents tangling duringdelivery and as shaft 1632 is slidably advanced or retracted relative toshaft 1604. Also, another portion of shaft 1632 is disposed underproximal portion 1622 of stent 1608. The second catheter 1630 may alsobe slidably advanced or retracted under the proximal portion 1622 ofstent 1608 so that the shaft 1632 passes through the side hole 1620 instent 1608. Radiopaque markers may be placed at different locations onthe shaft 1632, often near the balloon 1640 or stent 1642, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIG. 17A illustrates a catheter system 1700 having a distal daughtercatheter with a rapid exchange configuration a proximal mother catheterwith an over-the-wire configuration and an end to end zipper, or snapfitting. This embodiment is similar to that shown in FIG. 13A-13B, withthe major difference being the length of the snap fitting and thelocation of one of the guidewire ports. FIG. 17B more clearlyillustrates the features of the catheter system 1700 in FIG. 17A. Thestent delivery system 1700 includes a first catheter 1702, and a secondcatheter 1730. The first catheter 1702 includes an elongate shaft 1704with a radially expandable balloon 1706 disposed near a distal end ofthe elongate shaft 1704. A stent 1708 having a proximal portion 1722, adistal portion 1714 and a side hole 1720 is disposed over the balloon1706. The distal portion 1714 is crimped to the balloon 1706 to preventejection during delivery, while the proximal portion 1722 is partiallycrimped to the balloon 1706 so the second catheter 1730 may be slidablyadvanced under the proximal portion 1722 of stent 1708. The firstcatheter is an over-the-wire (OTW) catheter having a guidewire lumen1712 extending from the distal guidewire port 1710 at the distal end ofthe elongate shaft 1704 to the proximal end of the elongate shaft 1704into Y-adapter 1714 having a connector 1716. The connector 1716 ispreferably a Luer connector and this allows easy coupling with a syringeor other device for lumen flushing or injecting contrast media. Whenunconnected, the guidewire lumen 1712 exits via connector 1716. A secondconnector 1718, also preferably a Luer connector allows attachment of anIndeflator or other device to the catheter for inflation of the balloon1706 via an inflation lumen (not shown) in the elongate shaft 1704. Thefirst catheter 1702 also includes a zipper or snap fitting 1724 coupledto the elongate shaft 1704. The snap fit tube 1724 may be coextrudedwith the first shaft 1704, or it may be bonded or otherwise attachedthereto using techniques known to those skilled in the art. The snap fit1724 may alternatively be coupled with the other shaft 1732. The snapfitting 1724 includes a central channel 1726 extending therethrough andis sized to slidably receive a portion of the second catheter 1730. Anelongate slot 1745 extends along the entire length of the snap fitting1724 and is sized so that shaft 1736 may snapped into the centralchannel 1726. The snap fitting 1724 may extend from the distal end ofconnectors 1714, 1744 to the proximal end of balloon 1706, or it may beshorter, extending only partially between the connectors 1714, 1744 andthe balloon 1706. FIG. 17C illustrates a partial cross-section of FIG.17B taken along the line C-C and shows shaft 1704 with the snap fitting1724. Radiopaque markers may be placed at different locations along theshaft 1704, often near the balloon 1706 and/or stent 1708, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

The second catheter 1730 includes an elongate shaft 1732 with a radiallyexpandable balloon 1740 disposed near a distal end of the elongate shaft1732. A stent 1742 is disposed over balloon 1740. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1742 is shorter than the working length of theballoon 1740 so that a proximal portion of the balloon 1740 isunconstrained by the stent 1742 and this unconstrained portion of theballoon 1740 may be slidably advanced or retracted through side hole1720 and under proximal portion 1722 of stent 1708 as will be discussedbelow. Stent 1742 is crimped to balloon 1740 to prevent ejection duringdelivery. At least a portion of balloon 1740, and stent 1742 aredistally offset relative to balloon 1706 and stent 1708 so as tominimize profile of the device. In this embodiment the distal stent 1742may be deployed in a main branch of the vessel and the other stent 1708may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1742 may be deployed in a side branch of a vessel and theother stent 1708 may be deployed in the main branch of a vessel. Thesecond catheter 1730 is a rapid exchange catheter (RX) having aguidewire lumen 1734 extending from the distal guidewire port 1738 atthe distal end of the elongate shaft 1732 to a proximal guidewire port1736 which is closer to the distal port 1738 than the proximal end ofthe catheter shaft 1732. The proximal guidewire port 1736 is alsounobstructed by the snap fitting 1724 and preferably distal thereto. Aconnector 1744, preferably a Luer connector is connected to the proximalend of the elongate shaft 1732 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 1732for inflation of balloon 1740. A portion of shaft 1732 is snapped intothe central channel 1726 of the snap fitting 1724 via slit 1745, andthus shaft 1732 may slide in channel 1726. This helps keep the twocatheter shafts 1704, 1732 parallel and prevents tangling duringdelivery and as shaft 1732 is slidably advanced or retracted relative toshaft 1704. Also, another portion of shaft 1732 is disposed underproximal portion 1722 of stent 1708. The second catheter 1730 may alsobe slidably advanced or retracted under the proximal portion 1722 ofstent 1708 so that the shaft 1732 passes through the side hole 1720 instent 1708. Radiopaque markers may be placed at different locations onthe shaft 1732, often near the balloon 1740 or stent 1742, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIG. 18A illustrates a catheter system 1800 having a proximal mothercatheter with a rapid exchange configuration and a distal daughtercatheter with an end to end zipper or snap fitting. FIG. 18A is similarto the embodiment of FIG. 14A-14B, with the major difference being thelength of the snap fitting and the location of one of the guidewireports. FIG. 18B more clearly illustrates the features of the cathetersystem 1800 in FIG. 18A. The stent delivery system 1800 includes a firstcatheter 1802, and a second catheter 1830. The first catheter 1802includes an elongate shaft 1804 with a radially expandable balloon 1806disposed near a distal end of the elongate shaft 1804, and a stent 1808disposed over the balloon 1806. The stent 1808 may be the same length asthe working length of the balloon 1808, or it may be shorter. Inpreferred embodiments, the stent 1808 is shorter than the working lengthof balloon 1806 such that a proximal portion of balloon 1806 remainsunconstrained by stent 1808. The proximal portion of balloon 1806 may beslidably advanced and retracted under stent 1842 via side hole 1820.Stent 1808 is crimped to the balloon 1806 to prevent ejection duringdelivery. The first catheter is an over-the-wire (OTW) catheter having aguidewire lumen 1812 extending from the distal guidewire port 1810 atthe distal end of the elongate shaft 1804 to the proximal end of theelongate shaft 1804 into Y-adapter 1814 having a connector 1816. Theconnector 1816 is preferably a Luer connector and this allows easycoupling with a syringe or other device for lumen flushing or injectingcontrast media. When unconnected, the guidewire lumen 1812 exits viaconnector 1816. A second connector 1818, also preferably a Luerconnector allows attachment of an Indeflator or other device to thecatheter for inflation of the balloon 1806 via an inflation lumen (notshown) in the elongate shaft 1804. The first catheter 1802 also includesa zipper or snap fitting 1824 coupled to the elongate shaft 1804. Thesnap fit tube 1824 may be coextruded with the first shaft 1804, or itmay be bonded or otherwise attached thereto using techniques known tothose skilled in the art. The snap fit 1824 may alternatively be coupledwith the other shaft 1832. The snap fitting 1824 includes a centralchannel 1826 extending therethrough and is sized to slidably receive aportion of the second catheter 1830. An elongate slot 1845 extends alongthe entire length of the snap fitting 1824 and is sized so that shaft1836 may snapped into the central channel 1826. FIG. 18C illustrates apartial cross-section of FIG. 18B taken along the line C-C and showsshaft 1804 with the snap fitting 1824. The snap fitting 1824 may extendfrom the distal end of connectors 1814, 1844 to the proximal end ofballoon 1840, or it may be shorter, extending only partially between theconnectors 1814, 1844 and the balloon 1806. Radiopaque markers may beplaced at different locations along the shaft 1804, often near theballoon 1806 and/or stent 1808, to help mark the proximal and distalends of the stent or balloon, as well to facilitate alignment of the twocatheters during stent deployment, as discussed elsewhere in thisspecification.

The second catheter 1830 includes an elongate shaft 1832 with a radiallyexpandable balloon 1840 disposed near a distal end of the elongate shaft1832. A stent 1842 having a proximal portion 1822, a distal portion1814, and a side hole 1820 is disposed over balloon 1840. The distalportion 1814 is crimped to balloon 1840 to prevent ejection duringdelivery, while the proximal portion 1822 is partially crimped toballoon 1840 so elongate shaft 1804 may be slidably advanced orretracted under the proximal portion 1822 of stent 1842. The stent maypreferably have a length that matches the working length of the balloon,or the stent length may be shorter than the balloon working length. Atleast a portion of balloon 1806, and stent 1808 are distally offsetrelative to balloon 1840 and stent 1842 so as to minimize profile of thedevice. In this embodiment the distal stent 1808 may be deployed in amain branch of the vessel and the other stent 1842 may be deployed in aside branch of the vessel. Alternatively, the distal stent 1808 may bedeployed in a side branch of a vessel and the other stent 1842 may bedeployed in the main branch of a vessel. The second catheter 1830 is arapid exchange catheter (RX) having a guidewire lumen 1834 extendingfrom the distal guidewire port 1838 at the distal end of the elongateshaft 1832 to a proximal guidewire port 1836 which is closer to thedistal port 1838 than the proximal end of the catheter shaft 1832. Theproximal guidewire port 1836 is also unobstructed by the snap fitting1824 and preferably distal thereto. A connector 1844, preferably a Luerconnector is connected to the proximal end of the elongate shaft 1832and allows an Indeflator or other device to be coupled with an inflationlumen (not shown) in elongate shaft 1832 for inflation of balloon 1840.A portion of shaft 1832 is snapped into the central channel 1826 of thesnap fitting 1824 via slit 1845, and thus shaft 1832 may slide inchannel 1826. This helps keep the two catheter shafts 1804, 1832parallel and prevents tangling during delivery and as shaft 1832 isslidably advanced or retracted relative to shaft 1804. Also, a portionof shaft 1804 is disposed under proximal portion 1822 of stent 1842. Thefirst catheter 1802 may be slidably advanced or retracted under theproximal portion 1822 of stent 1842 so that the shaft 1804 passesthrough the side hole 1820 in stent 1842. Radiopaque markers may beplaced at different locations on the shaft 1832, often near the balloon1840 or stent 1842, to help mark the proximal and distal ends of thestent or balloon, as well to facilitate alignment of the two cathetersduring stent deployment, as discussed elsewhere in this specification.

FIG. 19A illustrates a catheter system 1900 having a dual rapid exchangedesign with an end to end zipper or snap fitting. FIG. 19A is similar tothe embodiment of FIG. 15A-15B, with the major difference being thelength of the snap fitting. FIG. 19B more clearly illustrates thefeatures of the catheter system 1900 in FIG. 19A. The stent deliverysystem 1900 includes a first catheter 1902, and a second catheter 1930.The first catheter 1902 includes an elongate shaft 1904 with a radiallyexpandable balloon 1906 disposed near a distal end of the elongate shaft1904. A stent 1908 having a proximal portion 1922, a distal portion 1914and a side hole 1920 is disposed over the balloon 1906. The distalportion 1914 is crimped to the balloon 1906 to prevent ejection duringdelivery, while the proximal portion 1922 is partially crimped to theballoon 1906 so the second catheter 1930 may be slidably advanced underthe proximal portion 1922 of stent 1908. The first catheter is a rapidexchange catheter (RX) having a guidewire lumen 1912 extending from thedistal guidewire port 1910 at the distal end of the elongate shaft 1904to a proximal guidewire port 1911 which is closer to the distal port1910 than the proximal end of the catheter shaft 1904. A connector 1916is coupled with the proximal end of the elongate shaft 1904. Theconnector 1916 is preferably a Luer connector and this allows easycoupling with an Indeflator or other device for inflation of the balloon1906. The first catheter 1902 also includes a zipper or snap fitting1924 coupled to the elongate shaft 1904. The snap fit tube 1924 may becoextruded with the first shaft 1904, or it may be bonded or otherwiseattached thereto using techniques known to those skilled in the art. Thesnap fit 1924 may alternatively be coupled with the other shaft 1932.The snap fitting 1924 includes a central channel 1926 extendingtherethrough and is sized to slidably receive a portion of the secondcatheter 1930. An elongate slot 1945 extends along the entire length ofthe snap fitting 1924 and is sized so that shaft 1932 may snapped intothe central channel 1926. FIG. 19C illustrates a partial cross-sectionof FIG. 19B taken along the line C-C and shows shaft 1904 with the snapfitting 1924. Radiopaque markers may be placed at different locationsalong the shaft 1904, often near the balloon 1906 and/or stent 1908, tohelp mark the proximal and distal ends of the stent or balloon, as wellto facilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

The second catheter 1930 includes an elongate shaft 1932 with a radiallyexpandable balloon 1940 disposed near a distal end of the elongate shaft1932. A stent 1942 is disposed over balloon 1940. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 1942 is shorter than the working length of theballoon 1940 so that a proximal portion of the balloon 1940 isunconstrained by the stent 1942 and this unconstrained portion of theballoon 1940 may be slidably advanced or retracted through side hole1920 and under proximal portion 1922 of stent 1908 as will be discussedbelow. Stent 1942 is crimped to balloon 1940 to prevent ejection duringdelivery. At least a portion of balloon 1940, and stent 1942 aredistally offset relative to balloon 1906 and stent 1908 so as tominimize profile of the device. In this embodiment the distal stent 1942may be deployed in a main branch of the vessel and the other stent 1908may be deployed in a side branch of the vessel. Alternatively, thedistal stent 1942 may be deployed in a side branch of a vessel and theother stent 1908 may be deployed in the main branch of a vessel. Thesecond catheter 1930 is a rapid exchange catheter (RX) having aguidewire lumen 1934 extending from the distal guidewire port 1938 atthe distal end of the elongate shaft 1932 to a proximal guidewire port1936 which is closer to the distal port 1938 than the proximal end ofthe catheter shaft 1932. The proximal guidewire port 1936 is alsounobstructed by the snap fitting 1924 and may be distal thereto. Aconnector 1944, preferably a Luer connector is connected to the proximalend of the elongate shaft 1932 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 1932for inflation of balloon 1940. A portion of shaft 1932 is snapped intothe central channel 1926 of the snap fitting 1924 via slit 1945, andthus shaft 1932 may slide in channel 1926. This helps keep the twocatheter shafts 1904, 1932 parallel and prevents tangling duringdelivery and as shaft 1932 is slidably advanced or retracted relative toshaft 1904. Also, another portion of shaft 1932 is disposed underproximal portion 1922 of stent 1908. The second catheter 1930 may alsobe slidably advanced or retracted under the proximal portion 1922 ofstent 1908 so that the shaft 1932 passes through the side hole 1920 instent 1908. Radiopaque markers may be placed at different locations onthe shaft 1932, often near the balloon 1940 or stent 1942, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIG. 20A illustrates a catheter system 2000 having a dual over the wiredesign with an end to end zipper or snap fitting. FIG. 20A is similar tothe embodiment of FIG. 16A-16B, with the major difference being thelength of the snap fitting. FIG. 20B more clearly illustrates thefeatures of the catheter system 2000 in FIG. 20A. The stent deliverysystem 2000 includes a first catheter 2002, and a second catheter 2030.The first catheter 2002 includes an elongate shaft 2004 with a radiallyexpandable balloon 2006 disposed near a distal end of the elongate shaft2004. A stent 2008 having a proximal portion 2022, a distal portion 2014and a side hole 2020 is disposed over the balloon 2006. The distalportion 2014 is crimped to the balloon 2006 to prevent ejection duringdelivery, while the proximal portion 2022 is partially crimped to theballoon 2006 so the second catheter 2030 may be slidably advanced underthe proximal portion 2022 of stent 2008. The first catheter is anover-the-wire (OTW) catheter having a guidewire lumen 2012 extendingfrom the distal guidewire port 2010 at the distal end of the elongateshaft 2004 to the proximal end of the elongate shaft 2004 into Y-adapter2014 having a connector 2016. The connector 2016 is preferably a Luerconnector and this allows easy coupling with a syringe or other devicefor lumen flushing or injecting contrast media. When unconnected, theguidewire lumen 2012 exits via connector 2016. A second connector 2018,also preferably a Luer connector allows attachment of an Indeflator orother device to the catheter for inflation of the balloon 2006 via aninflation lumen (not shown) in the elongate shaft 2004. The firstcatheter 2002 also includes a zipper or snap fitting 2024 coupled to theelongate shaft 2004. The snap fit tube 2024 may be coextruded with thefirst shaft 2004, or it may be bonded or otherwise attached theretousing techniques known to those skilled in the art. The snap fit 2024may alternatively be coupled with the other shaft 2032. The snap fitting2024 includes a central channel 2026 extending therethrough and is sizedto slidably receive a portion of the second catheter 2030. An elongateslot 2045 extends along the entire length of the snap fitting 2024 andis sized so that shaft 2036 may snapped into the central channel 2026.FIG. 20C illustrates a partial cross-section of FIG. 20B taken along theline C-C and shows shaft 2004 with the snap fitting 2024. Radiopaquemarkers may be placed at different locations along the shaft 2004, oftennear the balloon 2006 and/or stent 2008, to help mark the proximal anddistal ends of the stent or balloon, as well to facilitate alignment ofthe two catheters during stent deployment, as discussed elsewhere inthis specification.

The second catheter 2030 includes an elongate shaft 2032 with a radiallyexpandable balloon 2040 disposed near a distal end of the elongate shaft2032. A stent 2042 is disposed over balloon 2040. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 2042 is shorter than the working length of theballoon 2040 so that a proximal portion of the balloon 2040 isunconstrained by the stent 2042 and this unconstrained portion of theballoon 2040 may be slidably advanced or retracted through side hole2020 and under proximal portion 2022 of stent 2008 as will be discussedbelow. Stent 2042 is crimped to balloon 2040 to prevent ejection duringdelivery. At least a portion of balloon 2040, and stent 2042 aredistally offset relative to balloon 2006 and stent 2008 so as tominimize profile of the device. In this embodiment the distal stent 2042may be deployed in a main branch of the vessel and the other stent 2008may be deployed in a side branch of the vessel. Alternatively, thedistal stent 2042 may be deployed in a side branch of a vessel and theother stent 2008 may be deployed in the main branch of a vessel. Thesecond catheter 2030 is an over-the-wire (OTW) catheter having aguidewire lumen 2034 extending from the distal guidewire port 2038 atthe distal end of the elongate shaft 2032 to the proximal end of theelongate shaft 2032 into Y-adapter 2046 having a connector 2048. Theconnector 2048 is preferably a Luer connector and this allows easycoupling with a syringe or other device for lumen flushing or injectingcontrast media. When unconnected, the guidewire lumen 2034 exits viaconnector 2048. A second connector 2044, also preferably a Luerconnector allows attachment of an Indeflator or other device to thecatheter for inflation of the balloon 2040 via an inflation lumen (notshown) in the elongate shaft 2032. A portion of shaft 2032 is snappedinto the central channel 2026 of the snap fitting 2024 via slit 2045,and thus shaft 2032 may slide in channel 2026. This helps keep the twocatheter shafts 2004, 2032 parallel and prevents tangling duringdelivery and as shaft 2032 is slidably advanced or retracted relative toshaft 2004. Also, another portion of shaft 2032 is disposed underproximal portion 2022 of stent 2008. The second catheter 2030 may alsobe slidably advanced or retracted under the proximal portion 2022 ofstent 2008 so that the shaft 2032 passes through the side hole 2020 instent 2008. Radiopaque markers may be placed at different locations onthe shaft 2032, often near the balloon 2040 or stent 2042, to help markthe proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIGS. 21A, 22A, 23A, and 24A illustrate catheters that can be used withan alternative embodiment where the mother catheter is provided to theoperator with a mother stent that is crimped on the distal portion ofthe mother catheter balloon. The proximal portion of the mother stent isuncrimped or partially crimped. The operator can mount any commerciallyavailable catheter or balloon on a wire through the mother stentproximal end and exit out the side hole of the mother stent. Theoperator can align the catheters to suit the patient's anatomy and crimpthe proximal portion of the mother stent. The operator can crimp thestent tightly so that the catheters do not move relative to each other.It is possible for the operator to place the catheters at thebifurcation and if necessary pullback on the commercially availablecatheter to adjust the alignment if necessary. Then the operator cangently push the system distally to ensure complete apposition.

FIG. 21A illustrates a catheter system 2100 having a distal daughtercatheter with a rapid exchange configuration and a proximal mothercatheter with an over-the-wire configuration. FIG. 21B more clearlyillustrates the features of the catheter system 2100 in FIG. 21A. Thestent delivery system 2100 includes a first catheter 2102, and a secondcatheter 2130. The first catheter 2102 includes an elongate shaft 2104with a radially expandable balloon 2106 disposed near a distal end ofthe elongate shaft 2104. A stent 2108 having a proximal portion 2122, adistal portion 2114 and a side hole 2120 is disposed over the balloon2106. The distal portion 2114 is crimped to the balloon 2106 to preventejection during delivery, while the proximal portion 2122 is partiallycrimped to the balloon 2106 so the second catheter 2130 may be slidablyadvanced under the proximal portion 2122 of stent 2108. The firstcatheter is an over-the-wire (OTW) catheter having a guidewire lumen2112 extending from the distal guidewire port 2110 at the distal end ofthe elongate shaft 2104 to the proximal end of the elongate shaft 2104into Y-adapter 2114 having a connector 2116. The connector 2116 ispreferably a Luer connector and this allows easy coupling with a syringeor other device for lumen flushing or injecting contrast media. Whenunconnected, the guidewire lumen 2112 exits via connector 2116. A secondconnector 2118, also preferably a Luer connector allows attachment of anIndeflator or other device to the catheter for inflation of the balloon2106 via an inflation lumen (not shown) in the elongate shaft 2104.Radiopaque markers may be placed at different locations along the shaft2104, often near the balloon 2106 and/or stent 2108, to help mark theproximal and distal ends of the stent or balloon, as well to facilitatealignment of the two catheters during stent deployment, as discussedelsewhere in this specification.

The second catheter 2130 includes an elongate shaft 2132 with a radiallyexpandable balloon 2140 disposed near a distal end of the elongate shaft2132. A stent 2142 is disposed over balloon 2140. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 2142 is shorter than the working length of theballoon 2140 so that a proximal portion of the balloon 2140 isunconstrained by the stent 2142 and this unconstrained portion of theballoon 2140 may be slidably advanced or retracted through side hole2120 and under proximal portion 2122 of stent 2108 as will be discussedbelow. Stent 2142 is crimped to balloon 2140 to prevent ejection duringdelivery. At least a portion of balloon 2140, and stent 2142 aredistally offset relative to balloon 2106 and stent 2108 so as tominimize profile of the device. In this embodiment the distal stent 2142may be deployed in a main branch of the vessel and the other stent 2108may be deployed in a side branch of the vessel. Alternatively, thedistal stent 2142 may be deployed in a side branch of a vessel and theother stent 2108 may be deployed in the main branch of a vessel. Thesecond catheter 2130 is a rapid exchange catheter (RX) having aguidewire lumen 2134 extending from the distal guidewire port 2138 atthe distal end of the elongate shaft 2132 to a proximal guidewire port2136 which is closer to the distal port 2138 than the proximal end ofthe catheter shaft 2132. A connector 2144, preferably a Luer connectoris connected to the proximal end of the elongate shaft 2132 and allowsan Indeflator or other device to be coupled with an inflation lumen (notshown) in elongate shaft 2132 for inflation of balloon 2140. Having aportion of shaft 2132 disposed under proximal portion 2122 of stent 2108helps keep catheter shafts 2104, 2132 parallel and prevents tanglingduring delivery and as shaft 2132 is slidably advanced or retractedrelative to shaft 2104. Also, another portion of shaft 2132 is disposedunder proximal portion 2122 of stent 2108. The second catheter 2130 mayalso be slidably advanced or retracted under the proximal portion 2122of stent 2108 so that the shaft 2132 passes through the side hole 2120in stent 2108. Radiopaque markers may be placed at different locationson the shaft 2132, often near the balloon 2140 or stent 2142, to helpmark the proximal and distal ends of the stent or balloon, as well tofacilitate alignment of the two catheters during stent deployment, asdiscussed elsewhere in this specification.

FIG. 22A illustrates a catheter system 2200 having a proximal mothercatheter with an over the wire design and a distal daughter catheterwith an over-the-wire configuration. FIG. 22B more clearly illustratesthe features of the catheter system 2200 in FIG. 22A. The stent deliverysystem 2200 includes a first catheter 2202, and a second catheter 2230.The first catheter 2202 includes an elongate shaft 2204 with a radiallyexpandable balloon 2206 disposed near a distal end of the elongate shaft2204, and a stent 2208 disposed over the balloon 2206. The stent 2208may be the same length as the working length of the balloon 2208, or itmay be shorter. In preferred embodiments, the stent 2208 is shorter thanthe working length of balloon 2206 such that a proximal portion ofballoon 2206 remains unconstrained by stent 2208. The proximal portionof balloon 2206 may be slidably advanced and retracted under stent 2242via side hole 2220. Stent 2208 is crimped to the balloon 2206 to preventejection during delivery. The first catheter is an over-the-wire (OTW)catheter having a guidewire lumen 2212 extending from the distalguidewire port 2210 at the distal end of the elongate shaft 2204 to theproximal end of the elongate shaft 2204 into Y-adapter 2214 having aconnector 2216. The connector 2216 is preferably a Luer connector andthis allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 2212 exits via connector 2216. A second connector 2218, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 2206 via aninflation lumen (not shown) in the elongate shaft 2204. Radiopaquemarkers may be placed at different locations along the shaft 2204, oftennear the balloon 2206 and/or stent 2208, to help mark the proximal anddistal ends of the stent or balloon, as well to facilitate alignment ofthe two catheters during stent deployment, as discussed elsewhere inthis specification.

The second catheter 2230 includes an elongate shaft 2232 with a radiallyexpandable balloon 2240 disposed near a distal end of the elongate shaft2232. A stent 2242 having a proximal portion 2222, a distal portion2214, and a side hole 2220 is disposed over balloon 2240. The distalportion 2214 is crimped to balloon 2240 to prevent ejection duringdelivery, while the proximal portion 2222 is partially crimped toballoon 2240 so elongate shaft 2204 may be slidably advanced orretracted under the proximal portion 2222 of stent 2242. The stent maypreferably have a length that matches the working length of the balloon,or the stent length may be shorter than the balloon working length. Atleast a portion of balloon 2206, and stent 2208 are distally offsetrelative to balloon 2240 and stent 2242 so as to minimize profile of thedevice. In this embodiment the distal stent 2208 may be deployed in amain branch of the vessel and the other stent 2242 may be deployed in aside branch of the vessel. Alternatively, the distal stent 2208 may bedeployed in a side branch of a vessel and the other stent 2242 may bedeployed in the main branch of a vessel. The second catheter 2230 is arapid exchange catheter (RX) having a guidewire lumen 2234 extendingfrom the distal guidewire port 2238 at the distal end of the elongateshaft 2232 to a proximal guidewire port 2236 which is closer to thedistal port 2238 than the proximal end of the catheter shaft 2232. Aconnector 2244, preferably a Luer connector is connected to the proximalend of the elongate shaft 2232 and allows an Indeflator or other deviceto be coupled with an inflation lumen (not shown) in elongate shaft 2232for inflation of balloon 2240. Having a portion of shaft 2204 disposedunder proximal portion 2222 of stent 2208 helps keep catheter 2202, 2232parallel and prevents tangling during delivery and as shaft 2204 isslidably advanced or retracted relative to shaft 2232. The firstcatheter 2202 may be slidably advanced or retracted under the proximalportion 2222 of stent 2242 so that the shaft 2204 passes through theside hole 2220 in stent 2242. Radiopaque markers may be placed atdifferent locations on the shaft 2232, often near the balloon 2240 orstent 2242, to help mark the proximal and distal ends of the stent orballoon, as well to facilitate alignment of the two catheters duringstent deployment, as discussed elsewhere in this specification.

FIG. 23A illustrates a catheter system 2300 having a dual rapid exchangedesign. FIG. 23B more clearly illustrates the features of the cathetersystem 2300 in FIG. 23A. The stent delivery system 2300 includes a firstcatheter 2302, and a second catheter 2330. The first catheter 2302includes an elongate shaft 2304 with a radially expandable balloon 2306disposed near a distal end of the elongate shaft 2304. A stent 2308having a proximal portion 2322, a distal portion 2314 and a side hole2320 is disposed over the balloon 2306. The distal portion 2314 iscrimped to the balloon 2306 to prevent ejection during delivery, whilethe proximal portion 2322 is partially crimped to the balloon 2306 sothe second catheter 2330 may be slidably advanced under the proximalportion 2322 of stent 2308. The first catheter is a rapid exchangecatheter (RX) having a guidewire lumen 2312 extending from the distalguidewire port 2310 at the distal end of the elongate shaft 2304 to aproximal guidewire port 2311 which is closer to the distal port 2310than the proximal end of the catheter shaft 2304. A connector 2316 iscoupled with the proximal end of the elongate shaft 2304. The connector2116 is preferably a Luer connector and this allows easy coupling withan Indeflator or other device for inflation of the balloon 2306.Radiopaque markers may be placed at different locations along the shaft2304, often near the balloon 2306 and/or stent 2308, to help mark theproximal and distal ends of the stent or balloon, as well to facilitatealignment of the two catheters during stent deployment, as discussedelsewhere in this specification.

The second catheter 2330 includes an elongate shaft 2332 with a radiallyexpandable balloon 2340 disposed near a distal end of the elongate shaft2332. A stent 2342 is disposed over balloon 2340. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 2342 is shorter than the working length of theballoon 2340 so that a proximal portion of the balloon 2340 isunconstrained by the stent 2342 and this unconstrained portion of theballoon 2340 may be slidably advanced or retracted through side hole2320 and under proximal portion 2322 of stent 2308 as will be discussedbelow. Stent 2342 is crimped to balloon 2340 to prevent ejection duringdelivery. At least a portion of balloon 2340, and stent 2342 aredistally offset relative to balloon 2306 and stent 2308 so as tominimize profile of the device. In this embodiment the distal stent 2342may be deployed in a main branch of the vessel and the other stent 2308may be deployed in a side branch of the vessel. Alternatively, thedistal stent 2342 may be deployed in a side branch of a vessel and theother stent 2308 may be deployed in the main branch of a vessel. Thesecond catheter 2330 is a rapid exchange catheter (RX) having aguidewire lumen 2334 extending from the distal guidewire port 2338 atthe distal end of the elongate shaft 2332 to a proximal guidewire port2336 which is closer to the distal port 2338 than the proximal end ofthe catheter shaft 2332. A connector 2344, preferably a Luer connectoris connected to the proximal end of the elongate shaft 2332 and allowsan Indeflator or other device to be coupled with an inflation lumen (notshown) in elongate shaft 2332 for inflation of balloon 2340. Having aportion of shaft 2332 disposed under proximal portion 2322 of stent 2208helps keep catheters 2302, 2332 parallel and prevents tangling duringdelivery and as shaft 2332 is slidably advanced or retracted relative toshaft 2304. The second catheter 2330 may also be slidably advanced orretracted under the proximal portion 2322 of stent 2308 so that theshaft 2332 passes through the side hole 2320 in stent 2308. Radiopaquemarkers may be placed at different locations on the shaft 2332, oftennear the balloon 2340 or stent 2342, to help mark the proximal anddistal ends of the stent or balloon, as well to facilitate alignment ofthe two catheters during stent deployment, as discussed elsewhere inthis specification.

FIG. 24A illustrates a catheter system 2400 having a dual over the wiredesign. FIG. 24B more clearly illustrates the features of the cathetersystem 2400 in FIG. 24A. The stent delivery system 2400 includes a firstcatheter 2402, and a second catheter 2430. The first catheter 2402includes an elongate shaft 2404 with a radially expandable balloon 2406disposed near a distal end of the elongate shaft 2404. A stent 2408having a proximal portion 2422, a distal portion 2414 and a side hole2420 is disposed over the balloon 2406. The distal portion 2414 iscrimped to the balloon 2406 to prevent ejection during delivery, whilethe proximal portion 2422 is partially crimped to the balloon 2406 sothe second catheter 2430 may be slidably advanced under the proximalportion 2422 of stent 2408. The first catheter is an over-the-wire (OTW)catheter having a guidewire lumen 2412 extending from the distalguidewire port 2410 at the distal end of the elongate shaft 2404 to theproximal end of the elongate shaft 2404 into Y-adapter 2414 having aconnector 2416. The connector 2416 is preferably a Luer connector andthis allows easy coupling with a syringe or other device for lumenflushing or injecting contrast media. When unconnected, the guidewirelumen 2412 exits via connector 2416. A second connector 2418, alsopreferably a Luer connector allows attachment of an Indeflator or otherdevice to the catheter for inflation of the balloon 2406 via aninflation lumen (not shown) in the elongate shaft 2404. Radiopaquemarkers may be placed at different locations along the shaft 2404, oftennear the balloon 2406 and/or stent 2408, to help mark the proximal anddistal ends of the stent or balloon, as well to facilitate alignment ofthe two catheters during stent deployment, as discussed elsewhere inthis specification.

The second catheter 2430 includes an elongate shaft 2432 with a radiallyexpandable balloon 2440 disposed near a distal end of the elongate shaft2432. A stent 2442 is disposed over balloon 2440. The stent may have alength that matches the working length of the balloon, or the stentlength may be shorter than the balloon working length. In preferredembodiments, the stent 2442 is shorter than the working length of theballoon 2440 so that a proximal portion of the balloon 2440 isunconstrained by the stent 2442 and this unconstrained portion of theballoon 2440 may be slidably advanced or retracted through side hole2420 and under proximal portion 2422 of stent 2408 as will be discussedbelow. Stent 2442 is crimped to balloon 2440 to prevent ejection duringdelivery. At least a portion of balloon 2440, and stent 2442 aredistally offset relative to balloon 2406 and stent 2408 so as tominimize profile of the device. In this embodiment the distal stent 2442may be deployed in a main branch of the vessel and the other stent 2408may be deployed in a side branch of the vessel. Alternatively, thedistal stent 2442 may be deployed in a side branch of a vessel and theother stent 2408 may be deployed in the main branch of a vessel. Thesecond catheter 2430 is an over-the-wire (OTW) catheter having aguidewire lumen 2434 extending from the distal guidewire port 2438 atthe distal end of the elongate shaft 2432 to the proximal end of theelongate shaft 2432 into Y-adapter 2446 having a connector 2448. Theconnector 2448 is preferably a Luer connector and this allows easycoupling with a syringe or other device for lumen flushing or injectingcontrast media. When unconnected, the guidewire lumen 2434 exits viaconnector 2448. A second connector 2444, also preferably a Luerconnector allows attachment of an Indeflator or other device to thecatheter for inflation of the balloon 2440 via an inflation lumen (notshown) in the elongate shaft 2432. Having a portion of shaft 2432disposed under proximal portion 2422 of stent 2408 helps keep catheters2402, 2430 parallel and prevents tangling during delivery and as shaft2432 is slidably advanced or retracted relative to shaft 2404. Thesecond catheter 2430 may also be slidably advanced or retracted underthe proximal portion 2422 of stent 2408 so that the shaft 2432 passesthrough the side hole 2420 in stent 2408. Radiopaque markers may beplaced at different locations on the shaft 2432, often near the balloon2440 or stent 2442, to help mark the proximal and distal ends of thestent or balloon, as well to facilitate alignment of the two cathetersduring stent deployment, as discussed elsewhere in this specification.

In any of the embodiments disclosed herein, commercially availablecatheters and commercially available stents may be matched up to formthe systems illustrated. In still other embodiments, commerciallyavailable catheters that are single use devices for treating a singlevessel may be mated together in various combinations and coupledtogether with a polymer sleeve. The operator chooses the two cathetersfor the patient's anatomy then slides a sized polymer sleeve over bothcatheters from the distal ends. Once the operator has the cathetersaligned the polymer sleeve can be treated with a heat or light source toshrink and bond the two catheters together with friction. The polymersleeve is made of typical polymers that can act as shrink wrap whentreated with a heat or light source. The polymer of the polymer sleevefor example could be manufactured with polyolefin, a chemical used inmanufacturing shrink wrap. The polymer sleeve would not crosslink orcovalently attach to the catheters, several types of polymers arecommercially available and have the requisite properties, thin, strong,not adhesive, and reaction times to their source of ten minutes or less.The polymer sleeves are typically 15 centimeters in length and havevarious diameters to suit typical catheter diameters 4 French to 20French. The operator can test that the bond is holding by applyingslight pressure prior to the procedure. If the polymer sleeve does nothold tightly the operator may elect to use a smaller diameter polymersleeve or use more than one polymer sleeve by placing the polymersleeves adjacent to each other. Alternatively, several smaller sleevesfrom 1 to 10 centimeters in length could be placed over severaldifferent portions of the catheters.

In any of the embodiments discussed herein, a therapeutic agent may bedisposed on the stent or balloon and eluted therefrom in a controlledmanner into the target treatment area such as a stenotic lesion.Exemplary therapeutic agents help inhibit restenosis, hyperplasia orhave other therapeutic benefits. Exemplary anti-hyperplasia agentsinclude anti-neoplastic drugs, such as paclitaxel, methotrexate, andbatimastal; antibiotics such as doxycycline, tetracycline, rapamycin,everolimus, biolimus A9, novolimus, myolimus, zotarolimus, and otheranalogs and derivatives of rapamycin, and actinomycin; aminosuppressants such as dexamethasone and methyl prednisolone; nitric oxidesources such as nitroprussides; estrogen; estradiols; and the like.Methods for applying the therapeutic agent to the stent or balloon arewell known to those skilled in the art, and have been described in thepatent and scientific literature.

Stent Delivery:

FIGS. 25A-30B illustrate an exemplary delivery sequence of a preferredembodiment in eight steps. Step 1 illustrates the introduction of a0.035 inch guidewire up to the bifurcation. Step 2 illustrates thetracking of a guide catheter over the guidewire. Step 3 illustrates theremoval of the guidewire and placement position of the guide catheter.Step 4 illustrates the tracking and placement of a rapid exchangecompatible wire in the daughter vessel and an over the wire compatiblewire in the mother vessel. Step 5A & 5B illustrate tracking of thecatheter system distally over both the guidewires. Step 6A illustratesthe inflation of the daughter balloon and placement of the daughterstent and partial deployment of the mother stent. Step 6B illustratesthe inflation of the mother balloon to place the distal portion of themother stent in the mother vessel. Step 7A illustrates mother stent inthe main branch with side hole facing the daughter vessel. Step 7Billustrates the bifurcated stent partially in the daughter vessel anddaughter ostium completely opened and continuing on to the mothervessel.

In an alternative embodiment the delivery catheter mother balloonshaving tapered ends to accommodate balloons and stents with non-uniformprofiles. For example, the proximal end of the daughter vessel stent maybe designed to have a larger circumference than the distal end tocompensate for the natural bifurcation anatomy. The daughter vesselballoon would likewise have a taper to properly expand the stent andensure complete apposition. Additionally, it is possible to design themother stent to expand differentially along its profile to compensatefor a larger arterial diameter at the carina or ostium. In other words,the proximal and distal ends of the mother vessel balloon and mothervessel stent would be smaller in circumference while the center portionof the mother vessel stent would have a larger circumference. In analternative embodiment the mother vessel balloon has tapered ends toaccommodate the distal balloon catheter portion and guidewire lumen.Further, the mother vessel balloon may be designed for differentialexpansion to accommodate natural vessel anatomy.

In a preferred embodiment the distal (daughter) balloon catheter portionis crimped with a half stent on a rapid exchange catheter. The daughtervessel stent is about 4-20 millimeters long and the daughter vesselballoon is approximately twice as long in length. The mother vesselstent is about 10-30 millimeters long, and is differentially crimped toallow independent operation of the daughter balloon catheter portion.The distal portion of the mother vessel stent is crimped tightly enoughto keep the entire stent from unintentionally dislodging during theprocedure. The proximal portion of the mother vessel stent is crimpedjust tightly enough to reduce the crossing profile and to allow thedaughter balloon catheter portion to be moved distal or proximalrelative to the mother balloon catheter portion. The proximal (mother)balloon catheter portion is an over the wire type design with the mothervessel balloon preferably about 3 centimeters proximal to the daughtervessel balloon. In an alternative embodiment a stent is designed toallow differential expansion of the middle portion of the stent relativeto the proximal and distal ends. In particular, the design facilitatesthe placement of the stent across a bifurcation lesion in the mothervessel because it has a larger circumference in the middle portionrelative to the ends than a stent with a constant profile. Further, theprofile can be adjusted so that the largest circumference can be placedproximal or distal to the midpoint of the stent. In the particularembodiment the largest circumference is distal to the midpoint of thestent, but could be easily reversed for variable patient anatomy.Partial crimping has the following features that make it possible tomaintain sufficient stent retention during delivery and placement andstill allows the secondary system adjustability and deliverability.

FIG. 31 shows a partially crimped bifurcation stent prior to placementon any balloon catheter. FIG. 32-34 illustrate an embodiment of thepresent invention in three steps. First, the bifurcation stent ispartially crimped over approximately one-third its distal portion ontothe mother catheter balloon and the daughter catheter is loaded throughthe mother catheter and mother stent where the daughter stent can becrimped separately. Second, the daughter stent is crimped and pulledback proximally to align the daughter stent proximal end near the motherstent distal end. Third and final the proximal portion of the motherstent can be crimped to reduce the outer diameter; yet still allowindependent movement of the two catheters relative to each other.

FIG. 35 illustrates a cross section of a mother and daughter ballooncatheter system without a daughter stent. The daughter catheter is ontop of the mother catheter. The mother stent is differentially crimpedaround the mother catheter balloon and daughter catheter because thedaughter catheter profile is smaller than the mother catheter. Thedifferential crimping is non-uniform and can create various crosssectional shapes to accommodate different catheter designs, balloondesigns, and stent designs. For example, pear shaped or a figure eightare possible configurations. The current embodiment is designed toreduce the profile as much as possible. In one preferred method ofmanufacturing a protective sheet is placed between the two catheters.The protective sheet only needs to cover the portions that will come incontact during the crimping process, then the protective sheet can beremoved.

FIG. 36 Illustrates a side view of the mother stent mounted on themother catheter balloon and the daughter catheter mounted on the mothercatheter through the mother stent. The distal portion of the motherstent will be crimped under standard conditions to hold stent firmly tothe mother balloon and mother catheter. The proximal portion of themother stent is the partially crimped to reduce the profile; but stillallows the daughter catheter freedom to move proximal or distal relativeto the mother catheter. This embodiment illustrates that the stent isdifferentially crimped in both the circumferential and longitudinaldirection. The amount of crimping will be determined by the stent designand size, catheter dimensions, and balloon dimensions; thus the crimpingis differential along the longitudinal axis.

FIG. 37 illustrates a side view of the mother stent mounted on themother catheter balloon and the daughter catheter mounted on the mothercatheter through the mother stent. The daughter catheter also includes astent that can be crimped under standard conditions. The distal portionof the mother stent will be crimped under standard conditions to holdstent firmly to the mother balloon and mother catheter. In oneexperiment, this arrangement was tested to determine the strength of thedistal crimping of the mother stent by pulling the daughter catheter andstent proximally; the results were that the daughter cathetersuccessfully passed through the crimped mother stent and still retainedthe daughter stent as well. Additional features may be utilized duringthe crimping process such as adding a slight positive internal pressureto the balloon so that the final balloon surface pillows about 0.002inch beyond the outer diameter of the stent. This process can yield adesign that protects the stent from engaging with the vessel thusreducing friction and improving stent retention at the same time.

Further, this process improves safety and reduces trauma to the vessel.While the above embodiment discloses a bifurcation stent that is crimpedat or about its distal half; this is not a limitation. The stent couldbe differentially crimped along its axis depending upon stent design,for example; if a hole in the side of a stent was not centered along theaxis. It may be preferential to have the distal crimped portion of thebifurcation stent extend just distal of the hole that the daughtercatheter to pass through. Alternatively, the distal crimped portioncould extend partially or entirely over the hole that the daughtercatheter passes through.

FIGS. 38A-38M more clearly illustrate an exemplary method of treating abifurcated vessel such as a bifurcated coronary artery. In FIG. 38A thebifurcated vessel BV includes a side branch vessel SB and a main branchvessel MB. The main branch has a main branch lesion ML, and the sidebranch has a side branch lesion SL. The angle between the side branchand the main branch is referred to as the bifurcation angle, and isindicated by θ. When the bifurcation angle θ is less than about 60 to 70degrees, the distal most stent of the system can be effectivelypositioned in the side branch. However, when the bifurcation angle isgreater than or equal to about 60 to 70 degrees, it becomes morechallenging to position the distal most stent in the side branch.Moreover, when the distal stent is retracted proximally toward the stenthaving the side hole (discussed below), the catheter shaft may bindagainst the side hole resulting in damage to the catheter shaft and/orstent. Therefore, in preferred embodiments, when the bifurcation angleis less than about 60 to 70 degrees, the distal most stent is preferablypositioned in the side branch and the proximal most stent is advancedinto the main branch. When the bifurcation angle is greater than orequal to about 60 to 70 degrees, the distal most stent is positioned inthe main branch and the other stent is positioned partially in the mainbranch and partially in the side branch. This is not intended to limitthe use of the catheter system, and either stent may be placed in eitherside branch or main branch depending on operator preference. In FIG.38B, a guidecatheter 3802 is advanced distally until its distal end isadjacent the bifurcation. A pair of guidewires GW1, GW2 are thenadvanced from the guidecatheter 3802 distally toward the bifurcationsuch that the first guidewire GW1 is advanced into the side branch SBand so that the distal tip of the first guidewire GW1 is distal of theside branch lesion SL. Similarly, the second guidewire GW2 is alsoadvanced distally in the main branch MB until the distal tip of thesecond guidewire GW2 is distal of the main branch lesion ML. In FIG.38C, a stent delivery system having a first catheter 3804 and a secondcatheter 3824 are advanced distally from the guide catheter 3802 towardthe bifurcation. The first delivery catheter 3804 includes an elongatecatheter shaft 3806 and a radially expandable balloon 3808 disposed overa distal portion of elongate shaft 3806. A balloon expandable stent 3816is disposed over the balloon 3808. In this exemplary embodiment, thestent is shorter than the working length of the balloon 3808, thereforea proximal portion 3810 of the balloon 3808 and a distal portion 3812are unconstrained by the stent 3816. The proximal portion 3810 may beretracted under a portion of the second stent 3842 and thus when balloon3808 is inflated, it will radially expand stent 3816 and a portion ofstent 3842. However, this is not intended to be limiting, and the stentlength may be substantially equal to the working length of the balloon,or it may have a shorter length as previously discussed. Proximalradiopaque marker 3820 and distal radiopaque marker 3818 help defineproximal and distal ends of the stent 3816 as well as proximal anddistal ends of the balloon 3808. The radiopaque markers will also beused to help align the two catheters during treatment of thebifurcation, as will be discussed below. The distal tip 3814 may be asoft durometer polymer thereby minimizing trauma to the vessel duringdelivery. A distal guidewire port 3822 extends from the distal tip 3814and allows guidewire GW1 to exit or enter a guidewire lumen (not shown)in the elongate shaft 3806. The first catheter 3804 may be a rapidexchange catheter or an over-the-wire catheter, examples of which havebeen disclosed above. The second catheter 3824 (best seen in FIG. 38D)includes an elongate catheter shaft 3826 with a radially expandableballoon 3828 disposed over a distal region of the elongate shaft 3826. Astent 3842 having a side hole 3844 is disposed over the balloon 3828.The length of the stent 3842 may be substantially the same as theworking length of the balloon 3828 or it may be less than the workinglength. In this exemplary embodiment, the stent 3842 has a lengthshorter than the working length of the balloon 3828 thus a proximalportion 3830 and a distal portion 3832 remain unconstrained by the stent3842. Proximal radiopaque marker 3836 and distal radiopaque marker 3834help define the proximal and distal ends of the stent 3842 as well asthe proximal and distal ends of the balloon 3828. The radiopaque markerswill also be used to help align the two catheters during treatment ofthe bifurcation, as will be discussed below. The distal tip 3838 may bea soft durometer polymer thereby minimizing trauma to the vessel duringdelivery. A distal guidewire port 3840 extends from the distal tip 3838and allows guidewire GW2 to exit or enter a guidewire lumen (not shown)in the elongate shaft 3826. The second catheter 3824 may be a rapidexchange catheter or an over-the-wire catheter, examples of which havepreviously been disclosed above.

Referring back to FIG. 38C, the bifurcation angle is less than about 60to 70 degrees, and the first catheter 3804 and the second catheter 3824are further advanced distally so that the first catheter tracks over thefirst guidewire GW1 into the side branch SB while the second catheter3824 tracks over the second guidewire GW2 in the main branch MB towardthe main branch lesion ML. Because the first catheter 3804 is coupledwith the second catheter 3824 via stent 3842, both catheters areadvanced distally simultaneously thereby reducing procedure time,although this is not meant to be limiting, as each catheter may beadvanced independently of the other. In this embodiment the firstballoon 3808 and first stent 3816 are distal to the second balloon 3828and second stent 3842. This axial offset minimizes the system profile.

In FIG. 38D, both catheters 3804, 3824 are advanced further distallytoward the bifurcation until the first stent 3816 is distal to the sidebranch lesion SL and the second stent 3842 traverses the main branchlesion ML and the side hole 3844 is adjacent the ostium of the sidebranch SB. Advancement of both catheters 3804, 3824 is again performedsimultaneously, although they could also be advanced independently ofone another. The operator will feel resistance against furtheradvancement of the catheters 3804, 3824 because as the catheters areadvanced further distally, the two catheter shafts 3806, 3826 willspread apart relative to one another as they are forced against thecarina of the bifurcation. However, a portion of the first elongateshaft 3806 is disposed under a portion of the second stent 3842,therefore the two shafts 3806, 3826 can only spread apart so far. Thus,when an operator feels resistance against further advancement of thecatheter shafts, the operator knows that both catheters 3804, 3824 andtheir associated stents and balloons are properly positioned relative tothe bifurcation.

In FIG. 38E, the first catheter 3804 is retracted proximally relative tothe second catheter 3824. Because a portion of the first catheter shaft3806 is disposed under a portion of the second stent 3842, the firstshaft 3806 is slidably retracted into side hole 3844 and the first shaft3806 and proximal portion 3810 of balloon 3808 are slidably retractedunder a portion of second stent 3842. The first shaft is proximallyretracted until proximal radiopaque marker 3820 lines up with proximalradiopaque marker 3836 so that a proximal end of the first stent 3816will be aligned with the side hole 3844 in the second stent 3842. Anoperator may feel resistance during retraction of the first elongateshaft 3806 relative to the second elongate shaft 3826 when the ends ofthe stents 3816, 3842 engage one another. Stent 3842 has a distalportion crimped to balloon 3828 to prevent ejection during delivery, anda proximal portion is partially crimped thereto or uncrimped to allowcatheter 3804 to slide thereunder. Crimping of the stent is disclosed ingreater detail in U.S. Patent Applications previously incorporated byreference above. The ends of the stents may butt up against one another,overlap with one another, interleave with one another, or combinationsthereof. Additional details related to the engagement of the stents isdisclosed below. Both stents 3816, 3842 are disposed adjacent theirrespective lesions SL, ML, and the side hole 3844 is in rough alignmentwith the ostium to the side branch SB and the side branch stent 3816.

In FIG. 38F, the balloon 3808 is radially expanded, often with contrastmedium, saline, or a combination thereof thereby radially expanding thefirst stent 3816 into engagement with the side branch lesion SL and thewalls of the side branch. Expansion of balloon 3808 also helps align theproximal end of first stent 3816 with the ostium of the bifurcation. Aproximal portion 3810 and a distal portion 3812 of the balloon 3808 willalso expand, thus a proximal portion of the second stent 3842 will alsobe radially expanded. Expansion of the stents occurs simultaneously.Since a portion of balloon 3808 also passes through side hole 3844,expansion of balloon 3808 also partially expands the side hole 3844 andalso aligns the side hole 3844 with the ostium of the side branch andthe vessel. Thus expansion of balloon 3808 aligns stent 3842 and orientsthe side hole 3844 so that the proximal portion of stent 3842 becomescontiguous with stent 3816.

In FIG. 38G the balloon 3808 is contracted, and then in FIG. 38H theother balloon 3828 is radially expanded, with contrast medium, saline,or a combination thereof, thereby further radially expanding the secondstent 3842. Expansion of balloon 3828 expands the proximal portion ofthe stent 3842 into engagement with the main branch vessel wall and mainbranch lesion ML, and the distal portion of the stent 3842 is alsoradially expanded into the main branch vessel wall as well as the mainbranch lesion ML. The side hole 3844 is also further aligned with theostium of the side branch SB and the vessel.

Referring now to FIG. 38I, balloon 3828 is contracted and then bothballoons are simultaneously inflated in a “kissing balloon” technique asseen in FIG. 38J. Both balloons 3808, 3828 are inflated with contrastmedium, saline, or combinations thereof until they engage one anotherand are fully expanded in the main branch MB and side branch SB. Thekissing balloon technique ensures that both stents 3816, 3842 are fullyexpanded and in full apposition with their respective vessel wall andlesion, and in alignment with corresponding vessel. Additionally, thekissing balloon technique lines up the proximal end of the first sent3816 with the side hole 3844 in the second stent 3842, thereby ensuringthat continuous and smooth scaffolding from the main branch MB into theside branch SB. Also, the kissing balloons technique ensures that theside hole does not block the ostium to the side branch thereby avoiding“stent jailing,” or disrupting blood flow into the side branch.

In FIG. 38K, both balloons 3808, 3828 are contracted, and in FIG. 38Lboth catheters 3804, 3824 are retracted proximally. The catheters may beretracted simultaneously or independently of one another. The firstcatheter 3804 is retracted through both stents 3816, 3842 and alsopasses through the side hole 3844. The second catheter 3824 is retractedthrough the second stent 3842. In FIG. 38M, both catheters 3804, 3828have been removed, as well as the guide catheter 3802 and bothguidewires GW1, GW2. Stents 3816, 3842 remain implanted in at thebifurcation. Optionally, the stents or balloons may contain therapeuticagents such as those previously discussed, and these may elute out intothe lesion at a controlled rate in order to help prevent restenosis.

FIGS. 39A-39M more clearly illustrate another exemplary embodiment of amethod for treating a bifurcated vessel. This method is similar to thatpreviously disclosed, with the major difference being that thedistal-most catheter is used to treat the main branch vessel, and theproximal-most catheter is used to treat the side branch vessel. In theprevious embodiment, the distal-most catheter is used to treat the sidebranch vessel and the proximal-most catheter is used to treat the mainbranch.

In FIG. 39A, the bifurcated vessel BV includes a side branch vessel SBand a main branch vessel MB. The main branch has a main branch lesionML, and the side branch has a side branch lesion SL. The angle betweenthe side branch and the main branch is referred to as the bifurcationangle, and is indicated by θ. When the bifurcation angle θ is less thanabout 60 to 70 degrees, the distal most stent of the system can beeffectively positioned in the side branch. However, when the bifurcationangle is greater than or equal to about 60 to 70 degrees, it becomesmore challenging to position the distal most stent in the side branch.Moreover, when the distal stent is retracted proximally toward the stenthaving the side hole (discussed below), the catheter shaft may bindagainst the side hole resulting in damage to the catheter shaft and/orstent. Therefore, in preferred embodiments, when the bifurcation angleis less than about 60 to 70 degrees, the distal most stent is preferablypositioned in the side branch and the proximal most stent is advancedinto the main branch. When the bifurcation angle is greater than orequal to about 60 to 70 degrees, the distal most stent is positioned inthe main branch and the other stent is positioned partially in the mainbranch and partially in the side branch. This is not intended to limitthe use of the catheter system, and either stent may be placed in eitherside branch or main branch depending on operator preference. In FIG.39B, a guidecatheter 3902 is advanced distally into the vessel until itis adjacent the bifurcation and the lesions ML, SL. A first guidewireGW1 is advanced distally in the main branch MB until it is distal of themain branch lesion ML. A second guidewire is also advanced distallyuntil it enters the side branch SB and it is distal of the side branchlesion SL.

In FIG. 39C, a treatment system having a first catheter 3904, and asecond catheter 3924 are advanced distally through the guide catheter3902 toward the bifurcation. The two catheters 3904, 3924 may beadvanced independently of one another, or the two catheters maypreferably be advanced simultaneously. The first catheter 3904 includesan elongate shaft 3906 with a radially expandable balloon 3908 on adistal portion of the elongate shaft 3906. A stent 3922 is disposed overthe balloon 3908. The length of the stent 3922 may substantially matchthe working length of the balloon 3908, or the length of the stent 3922may be less than the working length of the balloon 3908 such that aproximal portion 3910 and a distal portion 3912 of the balloon remainsunconstrained by the stent 3922. A proximal radiopaque marker 3916 and adistal radiopaque marker 3914 may be used to help determine the proximaland distal ends of the balloon 3908 as well as the proximal and distalends of the stent 3922. A soft durometer polymer tip may be used on thedistal portion of the catheter shaft 3906 so as to prevent trauma to thevessel during delivery, and the catheter shaft 3906 has a distalguidewire port 3920 to allow a guidewire GW1 to enter or exit aguidewire lumen (not shown) in the catheter shaft 3906. The firstcatheter 3904 may be a rapid exchange catheter or it may be anover-the-wire catheter. The second catheter 3924 (best seen in FIG. 39D)includes an elongate shaft 3926 having a radially expandable balloon3928 on a distal portion thereof. A second stent 3934 is disposed overthe second balloon 3928. The stent length may substantially match theworking length of the balloon, or it may be less. In this embodiment,the length of stent 3934 is less than the working length of balloon3928, thus a proximal portion 3930 and a distal portion 3940 of theballoon remain unconstrained by the stent 3934. A portion of the firstelongate shaft 3906 is disposed under a proximal portion of the secondstent 3934, and the stent 3934 also has a side hole 3936 so that thefirst elongate shaft 3906 may exit therefrom. The first elongate shaft3906 may slide under the stent 3934 relative to the second elongateshaft 3926, thus a proximal portion 3910 of balloon 3908 is alsodisposed under stent 3934. When balloon 3908 is expanded, a proximalportion of stent 3934 will also be expanded. The second catheter shaft3926 also includes a proximal radiopaque marker 3932 and a distalradiopaque marker 3938 that help identify the proximal and distal endsof the balloon 3928 and the proximal and distal ends of the stent 3934.The second catheter 3924 also has a soft durometer polymer tip 3942 thathelps minimize trauma to the vessel during delivery, and a distalguidewire port 3944 allows a guidewire to be inserted or to exit from aguidewire lumen (not shown) in the elongate shaft 3926. The secondcatheter 3924 may be an over-the-wire catheter or it may be rapidexchange. The first stent 3922 and balloon 3908 are distal to the secondstent 3939 and second balloon 3928.

In FIG. 39D, the bifurcation angle θ is greater than about 60 to 70degrees. Both catheters 3904, 3924 are further advanced distally towardthe bifurcation until the first stent 3922 is distal to the main branchlesion ML, and the second stent 3934 is partially disposed in the sidebranch SB adjacent the side branch lesion SL, and the stent 3934 is alsodisposed in the main branch MB adjacent the main branch lesion ML. Theside hole 3936 also faces generally in the direction of the main branchvessel MB. Advancement of both catheters is preferably performedsimultaneously, although they could also be advanced independently ofone another. The operator will feel resistance against furtheradvancement of the catheters 3904, 3924 because as the catheters areadvanced further distally, the two catheter shafts 3906, 3926 willspread apart relative to one another as they are forced against thecarina of the bifurcation. However, a portion of the first elongateshaft 3906 is disposed under a portion of the second stent 3934,therefore the two shafts 3906, 3926 can only spread apart so far. Thus,when an operator feels resistance against further advancement of thecatheter shafts, the operator knows that both catheters 3904, 3924 andtheir associated stents and balloons are properly positioned relative tothe bifurcation.

In FIG. 39E the first catheter 3904 is retracted proximally relative tothe second catheter 3924 so a proximal portion 3910 of balloon 3908 isdisposed under stent 3934. Stent 3934 has a distal portion crimped toballoon 3928 so that it will not be ejected during delivery, and aproximal portion is partially crimped or uncrimped over balloon 3928 toallow shaft 3906 to slidably pass thereunder. Stent crimping isdescribed in greater detail in U.S. Patent Applications previouslyincorporated by reference above. Because a portion of the first cathetershaft 3906 is disposed under a portion of the second stent 3934, thefirst shaft 3906 is slidably retracted into side hole 3936 and the firstshaft 3906 is also slidably retracted under a portion of second stent3934. The first shaft is proximally retracted until proximal radiopaquemarker 3916 lines up with proximal radiopaque marker 3932 so that aproximal end of the first stent 3922 will be aligned with the side hole3936 in the second stent 3934. An operator may feel resistance duringretraction of the first elongate shaft 3906 relative to the secondelongate shaft 3926 when the ends of the stents 3922, 3934 engage oneanother. The ends of the stents may butt up against one another, overlapwith one another, interleave with one another, or combinations thereof.Additional details related to the engagement of the stents is disclosedbelow. Both stents 3922, 3934 are disposed adjacent their respectivelesions SL, ML, and the side hole 3936 is in rough alignment with themain branch vessel MB.

In FIG. 39F, the balloon 3908 is radially expanded, often with contrastmedium, saline, or a combination thereof thereby radially expanding thefirst stent 3922 into engagement with the main branch lesion ML and thewalls of the main branch. Also, the proximal end of stent 3922 isaligned with the vessel and also with side hole 3936. A proximal portionof the second stent 3934 is also aligned with, and expanded intoengagement with the main branch lesion ML and the walls of the mainbranch, while a distal portion of the second stent 3934 remainsunexpanded in the side branch SB. The first stent 3922 and the proximalportion of the second stent 3934 are radially expanded simultaneously.The inner surfaces of both stents form a smooth lumen for blood flowthrough the main branch. Since a portion of balloon 3908 also passesthrough side hole 3936, expansion of balloon 3908 also partially expandsthe side hole 3936 and also aligns the side hole 3936 with the mainbranch lumen. Thus expansion of balloon 3908 aligns a portion of stent3934 and orients the side hole 3936 so that a proximal portion of stent3934 becomes contiguous with stent 3922.

In FIG. 39G the balloon 3908 is contracted, and then in FIG. 39H theother balloon 3928 is radially expanded, with contrast medium, saline,or a combination thereof, thereby further radially expanding the secondstent 3934 and aligning it with the main branch and side branch.Expansion of balloon 3928 expands a distal portion of stent 3934 intoengagement with the side branch vessel wall and side branch lesion SL.The proximal portion of stent 3934 and side hole 3936 may also befurther expanded and aligned with the first stent 3922. The side hole isalso further aligned with the lumen of the main branch.

Referring now to FIG. 39I, balloon 3928 is contracted and then bothballoons are simultaneously inflated in a “kissing balloon” technique asseen in FIG. 39J. Both balloons 3908, 3928 are inflated with contrastmedium, saline, or combinations thereof until they engage one anotherand are fully expanded in the main branch MB and side branch SB. Thekissing balloon technique ensures that both stents 3922, 3934 are fullyexpanded and in full apposition with their respective vessel wall andlesion. Additionally, the kissing balloon technique lines up theproximal end of the first sent 3922 with the side hole 3936 in thesecond stent 3934, thereby ensuring that continuous and smoothscaffolding from the main branch MB into the side branch SB. Expandingboth balloons also ensure that both stents are aligned with theirrespective vessels. Alignment of the two stents is disclosed in greaterdetail below. Also, the kissing balloons technique ensures that the sidehole does not block the main branch or disrupting blood flow across thebifurcation.

In FIG. 39K, both balloons 3908, 3928 are contracted, and in FIG. 39Lboth catheters 3904, 3924 are retracted proximally. The catheters may beretracted simultaneously or independently of one another. The firstcatheter 3904 is retracted through both stents 3922, 3934 and alsopasses through the side hole 3936. The second catheter 3924 is retractedthrough the second stent 3934. In FIG. 39M, both catheters 3904, 3924have been removed, as well as the guide catheter 3802 and bothguidewires GW1, GW2. Stents 3922, 3934 remain implanted in at thebifurcation. Optionally, the stents or balloons may contain therapeuticagents such as those previously discussed, and these may elute out intothe lesion at a controlled rate in order to help prevent restenosis.

Any of the methods described above may use any of the stents disclosedherein in any of the system configurations described. Additionally, anyof the features previously described above may also be used. Therefore,one of skill in the art will appreciate that any number of combinationsmay made. For example, catheter systems may have any combination ofrapid exchange or over-the-wire configurations, with any of the stentsdisclosed herein, with or without a therapeutic agent on a stent or aballoon, and with or without any of the hollow exchange port, capturetube, removable capture tube, or snap fittings described above.

Stents:

The catheter systems and methods described above may use a commerciallyavailable stent for either the proximal or distal stent in the system.When a commercially available stent is used for the distal stent, itneed only be crimped to the distal balloon catheter. When thecommercially available stent is used for the proximal stent it may bepartially crimped to the proximal balloon such that a portion of asecond catheter shaft is slidably disposed under the stent and a portionof the second catheter shaft slidably passes through a side hole in thestent. The stent is crimped to the proximal balloon so that it is notdisplaced from the balloon during delivery, and also so the secondcatheter shaft can slide thereunder. FIGS. 40A-40E illustrate severalexamples of commercially available stents that may be used in cathetersystem configurations and methods described above, either as is, or withslight modification. For example, FIG. 40A illustrates the AbbottVascular Xience® drug eluting stent 4102 a. A portion of a cathetershaft may be disposed under the stent through its central channel andthe catheter may exit a side hole in the stent. A side hole may be thegap 4104 a created between adjacent struts in a cell, or the gap 4106 abetween axially adjacent cells. FIG. 40B illustrates the Cordis Cypher®stent 4102 b. Again a portion of a catheter shaft may be disposed underthe stent through its central channel and the catheter may exit a sidehole in the stent. A side hole may be the gap 4104 b created betweenadjacent struts in a cell, or the gap 4106 b between axially adjacentcells. FIG. 40C illustrates the Boston Scientific Taxus® Liberte® stent4102 c. A portion of a catheter shaft may be disposed under the stentthrough its central channel and the catheter may exit a side hole in thestent. A side hole may be the gap 4104 c created between adjacent strutsin a cell, or the gap 4106 c between axially adjacent cells. FIG. 40Dillustrates the Medtronic Endeavor® stent 4102 d. A portion of acatheter shaft may be disposed under the stent through its centralchannel and the catheter may exit a side hole in the stent. A side holemay be the gap 4104 d created between adjacent struts in a cell, or thegap 4106 d between axially adjacent cells. FIG. 40E illustrates aPalmaz-Schatz® stent 4104 e. A portion of a catheter shaft may bedisposed under the stent through its central channel and the cathetermay exit a side hole in the stent. A side hole may be the gap 4104 ecreated between adjacent struts in a cell, or the gap 4106 e betweenaxially adjacent segments. Other stents have been designed with sideholes that are specifically intended to treat bifurcations. These stentsmay also be used with the systems and method disclosed herein. Forexample, FIGS. 40E-40H illustrate several embodiments of stents fromBoston Scientific and are disclosed in detail in U.S. Pat. No.7,678,142. FIG. 40F shows a stent 4102 f after it has been unrolled andflattened having a side hole 4106 f. 40F illustrates a stent geometry(unrolled, plan view) where the struts create a side hole 4106 f thatallows access to a side branch, and that can accommodate a cathetershaft as described herein. The side hole may be formed by the spaces4104 f, 4108 f between struts. FIG. 40G illustrates another stentgeometry (unrolled, plan view) having a side hole 4106 g. Alternatively,the side hole may be formed by the spaces 4104 g, 4108 g between strutsor axial connectors. FIG. 40H illustrates still another stent geometry(unrolled, plan view) having a side hole 4106 h. The side hole may alsobe formed by the space between struts 4104 h or axial connectors 4108 h.In any of these embodiments, a catheter shaft may be slidably disposedunder a portion of the stent, and the catheter shaft may exit the sidehole. Additionally, any of the stents or balloons disclosed herein maycarry a therapeutic agent such as those described above for local drugdelivery. Also, while the stents disclosed herein are preferably balloonexpandable, one of skill in the art will appreciate that self-expanding,and hybrid balloon expandable/self-expanding stents may also be used.

Stent Alignment:

In addition to alignment of the stents with their respective vessels,alignment of the stents with one another is also accomplished with thedevice and methods disclosed here. FIGS. 41A-41C illustrate various waysa side branch stent can line up with a main branch stent. In FIG. 41A,the side branch SB is substantially perpendicular to the main branch MB,therefore the bifurcation angle θ is about 90 degrees. In thissituation, the proximal end 4206 of the side branch stent 4202 will besubstantially flush with the side hole 4208 in the main branch stent4204 (assuming proper deployment of both stents). This is desirablesince there are no gaps and hence no unscaffolded regions between thetwo stents 4202, 4204. However, when the bifurcation angle θ increases(FIG. 41B) or decreases (FIG. 41C), a portion of the side branch willremain unstented. For example, in FIG. 41B the bifurcation angleincreases and because of the right cylindrical shape of the stent, inwhich the end is perpendicular to the sidewalls of the stent, a gap 4210exits between the proximal end 4206 of the side branch stent 4202 andthe side hole 4208 of the main branch stent 4204. Similarly, in FIG.41C, when the bifurcation angle decreases, there is also a gap 4212between the proximal end 4206 of stent 4202 and the side hole 4208 ofstent 4204. FIG. 41C is typical of human anatomy, therefore the gap 4212often is upstream of the bifurcation. Gaps are undesirable since theyare unscaffolded and recoil and restenosis may occur in this region.Additionally, in the case where a stent is used for drug elution, thegap region may not receive any of the drug.

One possible solution for ensuring that the gap between a side branchstent and a main branch stent is eliminated or reduced is shown in FIG.42A. The side branch stent 4302 is a right cylindrical sent. The mainbranch stent 4304 has a side hole 4306 with struts that expand outwardlyinto the gap region, thereby ensuring continuous scaffolding. Analternative solution is to fabricate the proximal end 4310 of the sidebranch stent 4308 with its proximal end non-perpendicular to the centralaxis of the stent so that the proximal end of the side branch stentlines up with the side hole in the main branch stent 4312. Even usingthe geometries illustrated in FIG. 42A-42B still requires carefulalignment of the side branch stent with the main branch side hole.Therefore, it would be desirable to provide a stent geometry thatfacilitates alignment.

The ends of the side branch stent and the main branch stent mayintersect in several different ways thereby providing continuous anduniform coverage of the bifurcation. For example, in FIG. 43, a portion4406 of side branch stent 4402 may be disposed inside main branch stent4404. FIG. 44 shows a portion 4506 of the main branch stent 4504disposed inside the side branch stent 4502. Neither situation in FIG. 43or 44 are ideal as overlapping of stents may result in metal rubbing onmetal as well as possibly disrupting blood flow or causing stagnationpoints. A more desirable interface between stents is shown in FIG. 45where the end of the side branch stent 4602 butts up against the sidehole in main branch stent 4604. The interface region 4606 is desirablesince it provides continuous scaffolding of the vessel without gapsbetween ends of the stents. However, depending on the stent geometry,gaps may still exist between stents. Therefore, in preferredembodiments, the ends of the stents will interleave or interdigitatewith one another.

FIGS. 46A-46D illustrate several exemplary embodiments where the ends ofthe side branch stent and the side hole of the main branch stentinterleave with one another or interdigitate. For example, in FIG. 46A,a proximal end 4704 of side branch stent 4702 has a series of axiallyextending elements or fingers 4712 which interdigitate or interleavewith the laterally extending elements or fingers 4716 that extendlaterally from the side hole 4708 of main branch stent 4706. FIG. 46Billustrates an exemplary embodiment of interdigitating axial and lateralelements. A proximal end 4704 of side branch stent 4702 has a pluralityof axially extending elements 4712. The axially extending elements 4712are formed from a plurality of interconnected stent struts 4714, in thiscase forming a triangular shape. Similarly, the side hole 4708 of themain branch stent 4706 has a plurality of laterally extending elements4716 that are formed from a plurality of interconnected stent struts4718. In this case the laterally extending elements 4716 are formed intoa triangular shape. Thus the apex of one triangular shaped element fitsin between adjacent elements on the adjacent stent. Or alternatively,the peaks fit in the valleys, and the valleys receive the peaks.

FIG. 46C illustrates still another exemplary embodiment of interleavingor interdigitating elements. The proximal end 4704 of the side branchstent 4702 includes a strut 4720 formed into a series of peaks andvalleys. Similarly, the side hole 4708 of the main branch stent 4706will also have a strut 4722 that has been formed into a series of peaksand valleys. Therefore, the peaks of the side branch stent will fit intothe valleys of the adjacent main branch stent side hole, and similarlythe valleys of the side branch stent receive the peaks of the side hole.FIG. 46D illustrates yet another exemplary embodiment of interleaving orinterdigitation of stent ends. The proximal end 4704 of side branchstent 4702 includes a strut 4724 formed into a series of rectangularpeaks and valleys. The side hole 4708 of the main branch stent 4706 alsohas a strut 4726 formed into a series of rectangular peaks and valleys.The peaks and valleys interleave and interdigitate with one another.

Experiment #1

During animal testing, stent delivery systems similar to thoseillustrated in FIGS. 1A-1B, 2A-2B, 3A-3B, and 4A-4B were used to delivera first stent into a side branch and a second stent into a main branchat a bifurcated vessel. After alignment of the proximal end of the sidebranch stent with the side hole of the main branch stent, the stentswere radially expanded using methods described above. It was predictedthat the stents would either overlap with one another, or the stent endswould butt up against one another, or a gap would exist between the twostents. However, an unexpected result was achieved. Under fluoroscopy,the proximal end of the side branch stent was observed to interdigitatewith the side hole in the main branch, similar to FIG. 46A. Thisprovided uniform and continuous scaffolding along the main branch acrossthe bifurcation and into the side branch, without obstructing the ostiumto the side branch.

Balloon Configurations:

The balloons used to radially expand the stents described herein may becylindrical balloons having a constant diameter along the workinglength, or diameter may vary. When stenting a tapered vessel, it may beadvantageous to use a balloon which has a variable diameter balloon thatmore closely matches the vessel anatomy. For example, in FIG. 47A, atapered balloon 5006 is attached to the distal portion of shaft 5002. Asoft durometer tip 5004 prevents vessel trauma during delivery. Theballoon is tapered such that a proximal portion 5010 of the balloon hasa larger diameter than a distal portion 5006. Any taper may be used.FIG. 47B illustrates another embodiment of a balloon 5012 having aplurality of stepped regions 5014. The stepped regions may beincremented in any amount, and in preferred embodiments, a proximalportion 5016 of the balloon has a larger diameter than a distal portion5018. Any of these embodiments, or combinations thereof may be used inthe systems and methods described herein to treat a bifurcation. Use ofa tapered or stepped balloon allows a stent to be expanded to moreclosely match the vessel walls, where a proximal portion of the expandedstent has a larger diameter than a distal portion of the stent.

In addition to using catheters having rapid exchange or over-the-wireguidewire lumens, and tapered or stepped balloons, the balloon cathetersmay not always employ a guidewire lumen. Instead, a fixed wire may beattached to a distal end of the catheter. For example, FIG. 48illustrates an exemplary embodiment of a fixed wire catheter 5102 havinga balloon 5106 attached to a distal portion of the shaft 5104. A sectionof guidewire 5108 is fixedly attached to the distal end of the catheterand this fixed wire helps the catheter track through the vessels. Thefixed wire may have any number of shapes including straight, curved,J-tip, etc. This embodiment may be used with any of the systems andmethods disclosed herein, and it may or may not have a stent crimped tothe balloon. The fixed wire catheter may be used in main branch, or morepreferably it may be used in the side branch.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

What is claimed is:
 1. A method for treating a bifurcation in a vessel,said method comprising: providing a first delivery catheter, the firstdelivery catheter comprising a first elongate shaft, a first radiallyexpandable member coupled to a distal portion of the first elongateshaft, and a first radially expandable stent disposed over the firstradially expandable member, wherein the first radially expandable stenthas a sidewall with a side hole extending therethrough; providing asecond delivery catheter, the second delivery catheter comprising asecond elongate shaft, a second radially expandable member coupled to adistal portion of the second elongate shaft, and a second radiallyexpandable stent disposed over the second radially expandable member;advancing the first and second delivery catheters simultaneously towardthe bifurcation such that the first stent is disposed in one of a mainbranch or a side branch of the bifurcation, and the second stent isdisposed in the other of the main branch or side branch of thebifurcation, wherein during the advancing, the second radiallyexpandable stent is disposed distally away from the first radiallyexpandable stent such that the first and second radially expandablestents do not overlap with one another; retracting the second elongateshaft proximally such that the second radially expandable member passesthrough the side hole in the first radially expandable stent and atleast a portion of the second radially expandable member is disposedunder the first radially expandable stent; radially expanding the firststent and the second stent from a collapsed configuration to an expandedconfiguration which supports the main branch and the side branch; andoverlapping the first and second radially expandable members with oneanother during the radial expansion.
 2. The method of claim 1, whereinthe first radially expandable stent comprises a plurality of lateralelements extending laterally from the side hole and the second radiallyexpandable stent comprises a plurality of axial elements extendingaxially from a proximal end thereof, the method further comprisinginterdigitating the plurality of axial elements with the plurality oflateral elements.
 3. The method of claim 2, wherein the plurality oflateral elements comprise a plurality of interconnected struts formedinto a plurality of peaks and valleys.
 4. The method of claim 2, whereinthe plurality of axial elements comprise a plurality of struts formedinto a plurality of peaks and valleys.
 5. The method of claim 1, whereina first length is measured between a proximal end of the second radiallyexpandable stent and the side hole of the first radial expandable stent,and wherein a second length is measured between a distal end of thefirst radial expandable stent and the side hole of the first radialexpandable stent, the method further comprising maintaining the firstlength greater than the second length during the advancing.
 6. Themethod of claim 1, wherein a first length is measured between a proximalend of the second radially expandable stent and the side hole of thefirst radially expandable stent, and wherein a second length is measuredbetween a distal end of the first radial expandable stent and the sidehole of the first radial expandable stent, the method further comprisingmaintaining the second length less than the first length during theadvancing.
 7. The method of claim 1, wherein the second elongate shaftis disposed over the first radially expandable member during theadvancing.
 8. The method of claim 1, wherein a proximal portion of thesecond radially expandable member remains uncovered by the secondradially expandable stent.
 9. The method of claim 1, wherein the firstradially expandable member comprises a working length, and wherein theentire working length is substantially covered by the first radiallyexpandable stent.
 10. The method of claim 9, wherein the first or thesecond deliver catheter further comprises a therapeutic agent.
 11. Themethod of claim 10, wherein the therapeutic agent comprises ananti-restenosis drug.
 12. The method of claim 1, wherein the radiallyexpanding comprises radially expanding the first and second expandablemembers simultaneously.
 13. The method of claim 1, wherein the advancingcomprises advancing the first and second delivery catheters through ablood vessel.
 14. The method of claim 1, further comprising eluting atherapeutic agent from the first radially expandable stent or the secondradially expandable stent.
 15. The method of claim 1, wherein the firstelongate shaft comprises a first radiopaque marker, and the secondelongate shaft comprises a second radiopaque marker, and wherein theretracting comprises aligning the first and second radiopaque markerswith one another.
 16. The method of claim 1, wherein the advancing thefirst and second delivery catheters further comprises axially slidingthe second delivery catheter relative to the first delivery catheterwhile the first radially expandable stent is in a collapsedconfiguration.